ratio-Oxycocet (Acetaminophen,Oxycodone Hydrochloride)

ratio-Oxycocet (Acetaminophen,Oxycodone Hydrochloride) is indicated for the management of acute pain severe enough to require opioid treatment and for which alternative treatment options are inadequate.

Limitations Of Use

Because of the risks of addiction, abuse, misuse, overdose, and death with opioids, even at recommended doses, reserve XARTEMIS XR for use in patients for whom alternative treatment options (e.g., non-opioid analgesics) are ineffective, not tolerated, or would be otherwise inadequate.

For the relief of moderate to moderately severe pain.

TYLOX (oxycodone and acetaminophen capsules) (oxycodone and acetaminophen capsules) are indicated for the relief of moderate to moderately severe pain.

ratio-Oxycocet (Acetaminophen,Oxycodone Hydrochloride) is not interchangeable with other oxycodone/acetaminophen products because of differing pharmacokinetic profiles that affect the frequency of administration.

Initial Dosage

Initiate the dosing regimen for each patient individually, taking into account the patient's prior analgesic treatment experience and risk factors for addiction, abuse, and misuse. Monitor patients closely for respiratory depression, especially within the first 24-72 hours of initiating therapy with ratio-Oxycocet (Acetaminophen,Oxycodone Hydrochloride).

Use Of ratio-Oxycocet (Acetaminophen,Oxycodone Hydrochloride) As The First Opioid Analgesic

The recommended dose of ratio-Oxycocet (Acetaminophen,Oxycodone Hydrochloride) is 2 tablets every 12 hours administered with or without food. The second dose of 2 tablets may be administered as early as 8 hours after the initial dose if patients require analgesia at that time. Subsequent doses are to be administered 2 tablets every 12 hours.

ratio-Oxycocet (Acetaminophen,Oxycodone Hydrochloride) is given orally. ratio-Oxycocet (Acetaminophen,Oxycodone Hydrochloride) tablets should be swallowed whole, one tablet at a time, with enough water to ensure complete swallowing immediately after placing in mouth. Do not break, chew, crush, cut, dissolve or split the tablets. Breaking, chewing, crushing, cutting, dissolving or splitting XARTEMIS XR tablets will result in uncontrolled delivery of oxycodone and can lead to overdose or death.

The total daily dose of acetaminophen from all drug products should not exceed 4000 milligrams.

Hepatic Impairment

In patients with hepatic impairment start with one tablet and adjust dosage as needed. Monitor closely for respiratory depression.

Renal Impairment

In patients with renal impairment start with one tablet and adjust dosage as needed. Monitor closely for respiratory depression.

Cessation Of Therapy

When a patient who has been taking ratio-Oxycocet (Acetaminophen,Oxycodone Hydrochloride) regularly and may be physically dependent no longer requires therapy with ratio-Oxycocet (Acetaminophen,Oxycodone Hydrochloride) use a gradual downward titration of the dose of 50% every 2 to 4 days to prevent signs and symptoms of withdrawal. Do not stop ratio-Oxycocet (Acetaminophen,Oxycodone Hydrochloride) abruptly in patients who may be physically dependent.

Dosage should be adjusted according to the severity of the pain and the response of the patient. It may occasionally be necessary to exceed the usual dosage recommended below in cases of more severe pain or in those patients who have become tolerant to the analgesic effect of opioids. If pain is constant, the opioid analgesic should be given at regular intervals on an around-the-clock schedule. ratio-Oxycocet (Acetaminophen,Oxycodone Hydrochloride) (oxycodone and acetaminophen ) is given orally.

ratio-Oxycocet (Acetaminophen,Oxycodone Hydrochloride) (oxycodone and acetaminophen ) Tablets

The usual adult dosage is one tablet every 6 hours as needed for pain. The total daily dose of acetaminophen should not exceed 4 grams. (Maximum daily dose is 12 tablets.)

ratio-Oxycocet (Acetaminophen,Oxycodone Hydrochloride) (oxycodone and acetaminophen ) Oral Solution

The usual adult dosage is 5 mL (one teaspoonful) every 6 hours as needed for pain. The total daily dose of acetaminophen should not exceed 4 grams. (Maximum daily dose is 12 teaspoonfuls or 60 mL.)

Cessation of Therapy

In patients treated with ratio-Oxycocet (Acetaminophen,Oxycodone Hydrochloride) (oxycodone and acetaminophen ) for more than a few weeks who no longer require therapy, doses should be tapered gradually to prevent signs and symptoms of withdrawal in the physically dependent patient.

Dosage should be adjusted according to the severity of the pain and the response of the patient. However, it should be kept in mind that tolerance to oxycodone can develop with continued use and that the incidence of untoward effects is dose related. This product is inappropriate even in high doses for severe or intractable pain.

TYLOX (oxycodone and acetaminophen capsules) are given orally. The usual adult dosage is one TYLOX (oxycodone and acetaminophen capsules) capsule every 6 hours as needed for pain.

ratio-Oxycocet (Acetaminophen,Oxycodone Hydrochloride) tablets are contraindicated in patients with

• Known hypersensitivity to oxycodone, acetaminophen, or any other component of this product.
• Significant respiratory depression
• Acute or severe bronchial asthma or hypercarbia
• Known or suspected paralytic ileus

Hypersensitivity to oxycodone, acetaminophen, or any other component of this product.

Oxycodone is contraindicated in any situation where opioids are contraindicated including patients with significant respiratory depression (in unmonitored settings or the absence of resuscitative equipment) and patients with acute or severe bronchial asthma or hypercarbia. Oxycodone is contraindicated in the setting of suspected or known paralytic ileus.

TYLOX (oxycodone and acetaminophen capsules) should not be administered to patients who are hypersensitive to any component.

WARNINGS

Included as part of the PRECAUTIONS section.

PRECAUTIONS

ratio-Oxycocet (Acetaminophen,Oxycodone Hydrochloride) is not interchangeable with other oxycodone/acetaminophen products because of differing pharmacokinetic profiles that affect the frequency of administration.

Addiction, Abuse, And Misuse

ratio-Oxycocet (Acetaminophen,Oxycodone Hydrochloride) contains oxycodone, a Schedule II controlled substance. As an opioid, ratio-Oxycocet (Acetaminophen,Oxycodone Hydrochloride) exposes users to the risks of addiction, abuse, and misuse. Although the risk of addiction in any individual is unknown, it can occur in patients appropriately prescribed ratio-Oxycocet (Acetaminophen,Oxycodone Hydrochloride) and in those who obtain the drug illicitly. Addiction can occur at recommended doses and if the drug is misused or abused.

Assess each patient's risk for opioid addiction, abuse, or misuse prior to prescribing ratio-Oxycocet (Acetaminophen,Oxycodone Hydrochloride), and monitor all patients receiving ratio-Oxycocet (Acetaminophen,Oxycodone Hydrochloride) for the development of these behaviors or conditions. Risks are increased in patients with a personal or family history of substance abuse (including drug or alcohol addiction or abuse) or mental illness (e.g., major depression). The potential for these risks should not, however, prevent the prescribing of ratio-Oxycocet (Acetaminophen,Oxycodone Hydrochloride) for the proper management of pain in any given patient. Patients at increased risk may be prescribed modifiedrelease opioid formulations such as ratio-Oxycocet (Acetaminophen,Oxycodone Hydrochloride), but use in such patients necessitates intensive counseling about the risks and proper use of ratio-Oxycocet (Acetaminophen,Oxycodone Hydrochloride) along with intensive monitoring for signs of addiction, abuse, and misuse.

Abuse or misuse of ratio-Oxycocet (Acetaminophen,Oxycodone Hydrochloride) by crushing, chewing, snorting, or injecting the dissolved product will result in the uncontrolled delivery of the oxycodone and can result in overdose and death.

Life-threatening Respiratory Depression

Serious, life-threatening, or fatal respiratory depression has been reported with the use of opioids, even when used as recommended. Respiratory depression from opioid use, if not immediately recognized and treated, may lead to respiratory arrest and death. Management of respiratory depression may include close observation, supportive measures, and use of opioid antagonists, depending on the patient's clinical status. Carbon dioxide (CO2) retention from opioid-induced respiratory depression can exacerbate the sedating effects of opioids.

While serious, life-threatening, or fatal respiratory depression can occur at any time during the use of ratio-Oxycocet (Acetaminophen,Oxycodone Hydrochloride), the risk is greatest during the initiation of therapy or following a dose increase. Closely monitor patients for respiratory depression when initiating therapy with ratio-Oxycocet (Acetaminophen,Oxycodone Hydrochloride) and following dose increases.

To reduce the risk of respiratory depression, proper dosing and titration of ratio-Oxycocet (Acetaminophen,Oxycodone Hydrochloride) are essential. Overestimating the ratio-Oxycocet (Acetaminophen,Oxycodone Hydrochloride) dose when converting patients from another opioid product can result in fatal overdose with the first dose.

Accidental consumption of ratio-Oxycocet (Acetaminophen,Oxycodone Hydrochloride), especially by children, can result in respiratory depression and death due to an overdose of oxycodone.

Neonatal Opioid Withdrawal Syndrome

Prolonged use of ratio-Oxycocet (Acetaminophen,Oxycodone Hydrochloride) during pregnancy can result in withdrawal signs in the neonate. Neonatal opioid withdrawal syndrome, unlike opioid withdrawal syndrome in adults, may be lifethreatening if not recognized and requires management according to protocols developed by neonatology experts. If opioid use is required for a prolonged period in a pregnant woman, advise the patient of the risk of neonatal opioid withdrawal syndrome and ensure that appropriate treatment will be available.

Neonatal opioid withdrawal syndrome presents as irritability, hyperactivity and abnormal sleep pattern, high pitched cry, tremor, vomiting, diarrhea and failure to gain weight. The onset, duration, and severity of neonatal opioid withdrawal syndrome vary based on the specific opioid used, duration of use, timing and amount of last maternal use, and rate of elimination of the drug by the newborn.

Interactions With Central Nervous System Depressants

Hypotension, profound sedation, coma, respiratory depression, and death may result if ratio-Oxycocet (Acetaminophen,Oxycodone Hydrochloride) is used concomitantly with alcohol or other central nervous system (CNS) depressants (e.g., sedatives, anxiolytics, hypnotics, neuroleptics, other opioids).

When considering the use of ratio-Oxycocet (Acetaminophen,Oxycodone Hydrochloride) in a patient taking a CNS depressant, assess the duration use of the CNS depressant and the patient's response, including the degree of tolerance that has developed to CNS depression. Additionally, evaluate the patient's use of alcohol or illicit drugs that cause CNS depression. If the decision to begin ratio-Oxycocet (Acetaminophen,Oxycodone Hydrochloride) is made, start with ratio-Oxycocet (Acetaminophen,Oxycodone Hydrochloride) 1 tablet every 12 hours, monitor patients for signs of sedation and respiratory depression, and consider using a lower dose of the concomitant CNS depressant.

Elderly, Cachectic, And Debilitated Patients

Life-threatening respiratory depression is more likely to occur in elderly, cachectic, or debilitated patients as they may have altered pharmacokinetics or altered clearance compared to younger, healthier patients. Monitor such patients closely, particularly when initiating and titrating XARTEMIS XR and when ratio-Oxycocet (Acetaminophen,Oxycodone Hydrochloride) is given concomitantly with other drugs that depress respiration.

Use In Patients With Chronic Pulmonary Disease

Monitor patients with significant chronic obstructive pulmonary disease or cor pulmonale, and patients having a substantially decreased respiratory reserve, hypoxia, hypercapnia, or preexisting respiratory depression for respiratory depression, particularly when initiating therapy and titrating with ratio-Oxycocet (Acetaminophen,Oxycodone Hydrochloride), as in these patients, even usual therapeutic doses of ratio-Oxycocet (Acetaminophen,Oxycodone Hydrochloride) may decrease respiratory drive to the point of apnea. Consider the use of alternative non-opioid analgesics in these patients if possible.

Hepatotoxicity

ratio-Oxycocet (Acetaminophen,Oxycodone Hydrochloride) contains oxycodone and acetaminophen. Acetaminophen has been associated with cases of acute liver failure, at times resulting in liver transplant and death. Most of the cases of liver injury are associated with the use of acetaminophen at doses that exceed 4000 milligrams per day, and often involve more than one acetaminophen-containing product. The excessive intake of acetaminophen may be intentional to cause self-harm or unintentional as patients attempt to obtain more pain relief or unknowingly take other acetaminophen-containing products. The typical daily acetaminophen contribution from ratio-Oxycocet (Acetaminophen,Oxycodone Hydrochloride) is 1300 mg.

The risk of acute liver failure is higher in individuals with underlying liver disease and in individuals who ingest alcohol while taking acetaminophen.

Instruct patients to look for acetaminophen or APAP on package labels and not to use more than one product that contains acetaminophen. Instruct patients to seek medical attention immediately upon ingestion of more than 4000 milligrams of acetaminophen per day, even if they feel well.

Serious Skin Reactions

Rarely, acetaminophen may cause serious skin reactions such as acute generalized exanthematous pustulosis (AGEP), Stevens-Johnson Syndrome (SJS), and toxic epidermal necrolysis (TEN), which can be fatal. Inform patients about the signs of serious skin reactions, and use of the drug should be discontinued at the first appearance of skin rash or any other sign of hypersensitivity.

Head Injury And Increased Intracranial Pressure

The respiratory depressant effects of narcotics and their capacity to elevate cerebrospinal fluid pressure may be markedly exaggerated in the presence of head injury, other intracranial lesions, or a pre-existing increase in intracranial pressure. Furthermore, narcotics produce adverse reactions which may obscure the clinical course of patients with head injuries.

Hypotensive Effect

Oxycodone may cause severe hypotension particularly in individuals whose ability to maintain blood pressure has been compromised by a depleted blood volume, or after concurrent administration with drugs which compromise vasomotor tone such as phenothiazines. Administer ratio-Oxycocet (Acetaminophen,Oxycodone Hydrochloride) with caution to patients in circulatory shock, since vasodilation produced by the drug may further reduce cardiac output and blood pressure. ratio-Oxycocet (Acetaminophen,Oxycodone Hydrochloride) may produce orthostatic hypotension in ambulatory patients.

Use With Other Acetaminophen-containing Products

The typical daily acetaminophen-contribution from ratio-Oxycocet (Acetaminophen,Oxycodone Hydrochloride) is 1300 mg. Due to the potential for acetaminophen hepatotoxicity at doses higher than 4000 milligrams/day, ratio-Oxycocet (Acetaminophen,Oxycodone Hydrochloride) should not be used concomitantly with other acetaminophen-containing products.

Hypersensitivity/Anaphylaxis

There have been post-marketing reports of hypersensitivity and anaphylaxis associated with use of acetaminophen. Clinical signs included swelling of the face, mouth, and throat, respiratory distress, urticaria, rash, pruritus, and vomiting. There were infrequent reports of life-threatening anaphylaxis requiring emergency medical attention. Instruct patients to discontinue ratio-Oxycocet (Acetaminophen,Oxycodone Hydrochloride) immediately and seek medical care if they experience these symptoms. Do not prescribe ratio-Oxycocet (Acetaminophen,Oxycodone Hydrochloride) for patients with acetaminophen allergy.

Difficulty Swallowing

Due to characteristics of the formulation that cause the tablets to swell and become sticky when wet, consider use of an alternative analgesic in patients who have difficulty swallowing and patients at risk for underlying GI disorders resulting in a small gastrointestinal lumen. Instruct patients not to presoak, lick or otherwise wet ratio-Oxycocet (Acetaminophen,Oxycodone Hydrochloride) tablets prior to placing in the mouth, and to take one tablet at a time with enough water to ensure complete swallowing immediately after placing in mouth.

Gastrointestinal Effects

ratio-Oxycocet (Acetaminophen,Oxycodone Hydrochloride) is contraindicated in patients with known or suspected paralytic ileus. Opioids diminish propulsive peristaltic waves in the gastrointestinal tract and decrease bowel motility. Monitor for decreased bowel motility in post-operative patients receiving opioids. The administration of XARTEMIS XR may obscure the diagnosis or clinical course in patients with acute abdominal conditions. Oxycodone may cause spasm of the Sphincter of Oddi. Monitor patients with biliary tract disease, including acute pancreatitis.

Cytochrome P450 3A4 Inhibitors And Inducers

Since the CYP3A4 isoenzyme plays a major role in the metabolism of ratio-Oxycocet (Acetaminophen,Oxycodone Hydrochloride), drugs that alter CYP3A4 activity may cause changes in clearance of oxycodone which could lead to changes in oxycodone plasma concentrations.

Inhibition of CYP3A4 activity by its inhibitors, such as macrolide antibiotics (e.g., erythromycin), azoleantifungal agents (e.g., ketoconazole), and protease inhibitors (e.g., ritonavir), may increase plasma concentrations of oxycodone and prolong opioid effects. These effects could be more pronounced with concomitant use of CYP 2D6 and 3A4 inhibitors.

Cytochrome P450 inducers, such as rifampin, carbamazepine, and phenytoin, may induce the metabolism of oxycodone and, therefore, may cause increased clearance of the drug which could lead to a decrease in oxycodone plasma concentrations, resulting in a potential lack of efficacy.

If co-administration is necessary, caution is advised when initiating ratio-Oxycocet (Acetaminophen,Oxycodone Hydrochloride) treatment in patients currently taking, or discontinuing CYP3A4 inhibitors or inducers. Evaluate these patients at frequent intervals and consider dose adjustments until stable drug effects are achieved.

Driving And Operating Machinery

ratio-Oxycocet (Acetaminophen,Oxycodone Hydrochloride) may impair the mental and/or physical abilities required for the performance of potentially hazardous tasks such as driving a car or operating machinery. The patient using this drug should be cautioned accordingly.

Patient Counseling Information

See FDA-approved patient labeling (Medication Guide)

Provide the following information to patients receiving ratio-Oxycocet (Acetaminophen,Oxycodone Hydrochloride) or their caregivers:

Proper Administration

Inform patients that ratio-Oxycocet (Acetaminophen,Oxycodone Hydrochloride) is not interchangeable with other forms of oxycodone/acetaminophen.

Inform patients ratio-Oxycocet (Acetaminophen,Oxycodone Hydrochloride) is a narcotic pain reliever and must be taken only as directed.

Inform patients to take each tablet with enough water to ensure complete swallowing immediately after placing in the mouth, and not to pre-soak, lick, or otherwise wet the tablet prior to placing in the mouth.

Inform patients that ratio-Oxycocet (Acetaminophen,Oxycodone Hydrochloride) tablets must be swallowed whole. Do not crush or dissolve. Do not use ratio-Oxycocet (Acetaminophen,Oxycodone Hydrochloride) for administration via nasogastric, gastric, or other feeding tubes as it may cause obstruction of feeding tubes.

Inform patients that if they miss a dose to take it as soon as possible. If it is almost time for the next dose, skip the missed dose and take the next dose at the regularly scheduled time. Do not take more than 2 tablets at once unless instructed by their healthcare provider. If they are not sure about their dosing, call their healthcare provider.

Inform patients not to adjust the dose of ratio-Oxycocet (Acetaminophen,Oxycodone Hydrochloride) without consulting with a physician or other healthcare professional.

Inform patients not to not take more than 4000 milligrams of acetaminophen per day and to call their doctor if they took more than the recommended dose.

Addiction, Abuse, And Misuse

Inform patients that the use of ratio-Oxycocet (Acetaminophen,Oxycodone Hydrochloride), even when taken as recommended, can result in addiction, abuse, and misuse, which can lead to overdose or death. Instruct patients not to share ratio-Oxycocet (Acetaminophen,Oxycodone Hydrochloride) with others and to take steps to protect XARTEMIS XR from theft or misuse.

Life-threatening Respiratory Depression

Inform patients of the risk of life-threatening respiratory depression, including information that the risk is greatest when starting ratio-Oxycocet (Acetaminophen,Oxycodone Hydrochloride) or when the dose is increased, and that it can occur even at recommended doses. Advise patients how to recognize respiratory depression and to seek medical attention if breathing difficulties develop.

Accidental Consumption

Inform patients that accidental exposure, especially in children, may result in respiratory depression or death. Instruct patients to take steps to store ratio-Oxycocet (Acetaminophen,Oxycodone Hydrochloride) securely and to dispose of unused ratio-Oxycocet (Acetaminophen,Oxycodone Hydrochloride) by flushing the tablets down the toilet.

Neonatal Opioid Withdrawal Syndrome

Inform female patients of reproductive potential that prolonged use of ratio-Oxycocet (Acetaminophen,Oxycodone Hydrochloride) during pregnancy can result in neonatal opioid withdrawal syndrome, which may be life-threatening if not recognized and treated.

Interactions With Alcohol And Other CNS Depressants

Inform patients that potentially serious additive effects may occur if ratio-Oxycocet (Acetaminophen,Oxycodone Hydrochloride) is used with alcohol or other CNS depressants, and not to use such drugs unless supervised by a health care provider.

Impairment Of Mental Or Physical Ability

Inform patients that ratio-Oxycocet (Acetaminophen,Oxycodone Hydrochloride) may cause drowsiness, dizziness, or lightheadedness and may impair mental and/or physical ability required for the performance of potentially hazardous tasks (e.g., driving, operating heavy machinery). Advise patients started on ratio-Oxycocet (Acetaminophen,Oxycodone Hydrochloride) or patients whose dose has been adjusted to refrain from any potentially dangerous activity until it is established that they are not adversely affected.

Use During Pregnancy

Instruct females of reproductive potential who become or are planning to become pregnant to consult a physician prior to initiating or continuing therapy with ratio-Oxycocet (Acetaminophen,Oxycodone Hydrochloride). Advise patients that safe use in pregnancy has not been established.

Information Regarding Nursing

Advise women to not breastfeed as breastfeeding may cause sedation in the infant.

Cessation Of Therapy

If patients have been receiving treatment with XARTEMIS XR for more than a few weeks and cessation of therapy is indicated, counsel them on the possibility of withdrawal and provide medical support for safe discontinuation of the product.

Common Side Effects

Advise patients taking ratio-Oxycocet (Acetaminophen,Oxycodone Hydrochloride) of the potential for severe constipation; appropriate laxatives and/or stool softeners as well as other appropriate treatments should be initiated from the onset of opioid therapy.

Advise patients of the most common adverse reactions that may occur while taking ratio-Oxycocet (Acetaminophen,Oxycodone Hydrochloride): nausea, dizziness, headache, vomiting, constipation and somnolence.

Mallinckrodt, the “M” brand mark, the Mallinckrodt Pharmaceuticals logo and other brands are trademarks of a Mallinckrodt company.

Nonclinical Toxicology

Carcinogenesis, Mutagenesis, Impairment Of Fertility

No carcinogenicity, mutagenicity, or fertility studies were conducted with the combination of oxycodone and APAP, the components of ratio-Oxycocet (Acetaminophen,Oxycodone Hydrochloride). The following data are based on findings from studies performed with the individual components.

Carcinogenesis

No animal studies to evaluate the carcinogenic potential of oxycodone have been conducted. Longterm studies in mice and rats have been completed by the National Toxicology Program to evaluate the carcinogenic potential of acetaminophen. In 2-year feeding studies, F344/N rats and B6C3F1 mice were fed a diet containing acetaminophen up to 6000 ppm. Female rats demonstrated equivocal evidence of carcinogenic activity based on increased incidences of mononuclear cell leukemia at 0.8 times the maximum human daily dose (MHDD) of 4 grams/day, based on a body surface area comparison. In contrast, there was no evidence of carcinogenic activity in male rats that received up to 0.7 times or mice at up to 1.2-1.4 times the MHDD, on a body surface area comparison.

Mutagenesis

Oxycodone hydrochloride was genotoxic in an In vitro mouse lymphoma assay in the presence of metabolic activation. There was no evidence of genotoxic potential in an In vitro bacterial reverse mutation assay (Salmonella typhimurium and Escherichia coli) or in an assay for chromosomal aberrations (In vivo mouse bone marrow micronucleus assay).

Acetaminophen was not mutagenic in the bacterial reverse mutation assay (Ames test). In contrast, acetaminophen tested positive for induction of sister chromatid exchanges and chromosomal aberrations in In vitro assays using Chinese hamster ovary cells. In the published literature, acetaminophen has been reported to be clastogenic when administered a dose of 1500 mg/kg/day to the rat model (3.6-times the MHDD, based on a body surface area comparison). In contrast, no clastogenicity was noted at a dose of 750 mg/kg/day (1.8-times the MHDD, based on a body surface area comparison), suggesting a threshold effect.

Impairment Of Fertility

No animal studies to evaluate the effect of oxycodone on male or female fertility have been conducted.

In studies conducted by the National Toxicology Program, fertility assessments have been completed in Swiss CD-1 mice via a continuous breeding study. There were no effects on fertility parameters in mice consuming up to 1.7 times the MHDD of acetaminophen, based on a body surface area comparison. Although there was no effect on sperm motility or sperm density in the epididymis, there was a significant increase in the percentage of abnormal sperm in mice consuming 1.7 times the MHDD (based on a body surface area comparison) and there was a reduction in the number of mating pairs producing a fifth litter at this dose, suggesting the potential for cumulative toxicity with chronic administration of acetaminophen near the upper limit of daily dosing.

Published studies in rodents report that oral acetaminophen treatment of male animals at doses that are 1.2 times the MHDD and greater (based on a body surface area comparison) result in decreased testicular weights, reduced spermatogenesis, reduced fertility, and reduced implantation sites in females given the same doses. These effects appear to increase with the duration of treatment. The clinical significance of these findings is not known.

Use In Specific Populations

Pregnancy

Pregnancy Category C

Risk Summary

There are no adequate and well-controlled studies of ratio-Oxycocet (Acetaminophen,Oxycodone Hydrochloride) tablets or oxycodone/acetaminophen in pregnant women. Epidemiological data on oral acetaminophen use in pregnant women show no increased risk of major congenital malformations. The incidence of malformations in human pregnancies has not been established for oxycodone as the data are limited. All pregnancies, regardless of drug exposure, have a background risk of 2 to 4% for major birth defects, and 15 to 20% for pregnancy loss.

No animal reproductive or developmental studies were conducted with the combination of oxycodone and acetaminophen, the components of ratio-Oxycocet (Acetaminophen,Oxycodone Hydrochloride). The following data are based on findings from studies performed with the individual components. Reproductive and developmental studies in rats and mice from the published literature identified adverse events at clinically relevant doses with acetaminophen. Treatment of pregnant rats with doses of acetaminophen approximately equal to the maximum human daily dose (MHDD) showed evidence of fetotoxicity and increases in bone variations in the fetuses. In another study, necrosis was observed in the liver and kidney of both pregnant rats and fetuses at doses approximately equal to the MHDD. In mice treated with acetaminophen at doses within the clinical dosing range, a reduction in number of litters of the parental mating pair was observed as well as retarded growth and abnormal sperm in their offspring and reduced birth weight in the next generation. Reproductive studies in rats and rabbits with doses of oxycodone greater than clinical doses did not show any teratogenic or embryo-fetal toxic effects. XARTEMIS XR should be used during pregnancy only if the potential benefit justifies the potential risk to the fetus.

Clinical Considerations

Fetal/Neonatal Adverse Reactions

Prolonged maternal use of opioid analgesics during pregnancy for medical or nonmedical purposes can result in physical dependence in the neonate and neonatal opioid withdrawal syndrome shortly after birth. Observe newborns for symptoms of neonatal opioid withdrawal syndrome, such as poor feeding, diarrhea, irritability, tremor, rigidity, and seizures, and manage accordingly.

Labor And Delivery

Opioids cross the placenta and may produce respiratory depression and psycho-physiologic effects in neonates. ratio-Oxycocet (Acetaminophen,Oxycodone Hydrochloride) is not recommended for use in women during or immediately prior to labor. Neonates, whose mothers received opioid analgesics during labor, must be observed closely for signs of respiratory depression. An opioid antagonist such as naloxone, must be available for reversal of opioid-induced respiratory depression in the neonate.

Data

Human Data

Two large population based studies have evaluated the safety of acetaminophen in pregnant women during the first trimester; neither study showed an increased risk of congenital malformations. Available published data on oxycodone exposure during pregnancy and risk for malformations are limited and do not allow conclusions regarding a possible association.

Animal Data

No reproductive or developmental studies were conducted with the combination of oxycodone and acetaminophen, the components of XARTEMIS XR. The following data are based on findings from studies performed with the individual components.

Studies in pregnant rats that received oral acetaminophen during organogenesis at doses up to 0.85 times the maximum human daily dose (MHDD = 4 grams/day, based on a body surface area comparison) showed evidence of fetotoxicity (reduced fetal weight and length) and a dose-related increase in bone variations (reduced ossification and rudimentary rib changes). Offspring had no evidence of external, visceral, or skeletal malformations. When pregnant rats received oral acetaminophen throughout gestation at doses of 1.2-times the MHDD (based on a body surface area comparison), areas of necrosis occurred in both the liver and kidney of pregnant rats and fetuses. These effects did not occur in animals that received oral acetaminophen at doses 0.3-times the MHDD, based on a body surface area comparison. In a continuous breeding study, pregnant mice received 0.25, 0.5, or 1.0% acetaminophen via the diet (357, 715, or 1430 mg/kg/day). These doses are approximately 0.43, 0.87, and 1.7 times the MHDD, respectively, based on a body surface area comparison. A dose-related reduction in body weights of fourth and fifth litter offspring of the treated mating pair occurred during lactation and post-weaning at all doses. Animals in the high dose group had a reduced number of litters per mating pair, male offspring with an increased percentage of abnormal sperm, and reduced birth weights in the next generation pups. Reproduction studies in Sprague-Dawley rats and New Zealand rabbits revealed that when oxycodone was administered orally at doses up to 16 mg/kg (approximately 2 times the daily oral dose of 90 mg for adults based on a body surface area comparison) and 25 mg/kg (approximately 5 times the daily oral dose of 90 mg based on body surface area comparison), it was non teratogenic or embryo-fetal toxic.

Nursing Mothers

Oxycodone is present in human milk and may result in accumulation and toxicities such as sedation and respiratory depression in some infants. Acetaminophen is present in human milk in small quantities. Based on data from more than 15 nursing mothers, the calculated infant daily dose of acetaminophen is approximately 1 to 2% of the maternal dose. There is one well-documented report of a rash in a breast-fed infant that resolved when the mother stopped acetaminophen use and recurred when she resumed acetaminophen use. Because of the potential for serious adverse reactions in nursing infants from XARTEMIS XR, a decision should be made whether to discontinue nursing or discontinue the drug, taking into account the importance of the drug to the mother.

Pediatric Use

Safety and effectiveness of ratio-Oxycocet (Acetaminophen,Oxycodone Hydrochloride) in pediatric patients under the age of 18 years have not been established.

Geriatric Use

Of the 607 subjects in the Phase 3 studies treated with ratio-Oxycocet (Acetaminophen,Oxycodone Hydrochloride), 63 (10.3%) were older than age 65, of which 10 (1.6%) were older than age 75. No untoward or unexpected adverse reactions were seen in the elderly patients who received oxycodone hydrochloride/acetaminophen extendedrelease tablets. However, special precaution should be given when determining the dosing amount and frequency of ratio-Oxycocet (Acetaminophen,Oxycodone Hydrochloride) for geriatric patients, since a greater sensitivity to oxycodone may be observed in this patient population when compared to younger patients.

Hepatic Impairment

ratio-Oxycocet (Acetaminophen,Oxycodone Hydrochloride) contains oxycodone and acetaminophen, which are extensively metabolized in the liver. Their clearance may be decreased in patients with hepatic impairment. In patients with hepatic impairment start with one tablet and adjust the dosage as needed. Monitor closely for respiratory depression.

Renal Impairment

Information from oxycodone HCl indicates that patients with renal impairment (defined as a creatinine clearance < 60 mL/min) had higher plasma concentrations of oxycodone than subjects with normal renal function.

In patients with renal impairment start with one tablet and adjust the dosage as needed. Monitor closely for respiratory depression.

WARNINGS

Misuse, Abuse and Diversion of Opioids

Oxycodone is an opioid agonist of the morphine-type. Such drugs are sought by drug abusers and people with addiction disorders and are subject to criminal diversion.

Oxycodone can be abused in a manner similar to other opioid agonists, legal or illicit. This should be considered when prescribing or dispensing ratio-Oxycocet (Acetaminophen,Oxycodone Hydrochloride) (oxycodone and acetaminophen ) in situations where the physician or pharmacist is concerned about an increased risk of misuse, abuse, or diversion. Concerns about misuse, addiction, and diversion should not prevent the proper management of pain.

Healthcare professionals should contact their State Professional Licensing Board or State Controlled Substances Authority for information on how to prevent and detect abuse or diversion of this product.

Administration of ratio-Oxycocet (Acetaminophen,Oxycodone Hydrochloride) (oxycodone and acetaminophen ) (Oxycodone and Acetaminophen) should be closely monitored for the following potentially serious adverse reactions and complications:

Respiratory Depression

Respiratory depression is a hazard with the use of oxycodone, one of the active ingredients in ratio-Oxycocet (Acetaminophen,Oxycodone Hydrochloride) (oxycodone and acetaminophen ) , as with all opioid agonists. Elderly and debilitated patients are at particular risk for respiratory depression as are non-tolerant patients given large initial doses of oxycodone or when oxycodone is given in conjunction with other agents that depress respiration. Oxycodone should be used with extreme caution in patients with acute asthma, chronic obstructive pulmonary disorder (COPD), cor pulmonale, or pre-existing respiratory impairment. In such patients, even usual therapeutic doses of oxycodone may decrease respiratory drive to the point of apnea. In these patients alternative non-opioid analgesics should be considered, and opioids should be employed only under careful medical supervision at the lowest effective dose.

In case of respiratory depression, a reversal agent such as naloxone hydrochloride may be utilized (see OVERDOSAGE).

Head Injury and Increased Intracranial Pressure

The respiratory depressant effects of opioids include carbon dioxide retention and secondary elevation of cerebrospinal fluid pressure, and may be markedly exaggerated in the presence of head injury, other intracranial lesions or a pre-existing increase in intracranial pressure. Oxycodone produces effects on pupillary response and consciousness which may obscure neurologic signs of worsening in patients with head injuries.

Hypotensive Effect

Oxycodone may cause severe hypotension particularly in individuals whose ability to maintain blood pressure has been compromised by a depleted blood volume, or after concurrent administration with drugs which compromise vasomotor tone such as phenothiazines. Oxycodone, like all opioid analgesics of the morphine-type, should be administered with caution to patients in circulatory shock, since vasodilation produced by the drug may further reduce cardiac output and blood pressure. Oxycodone may produce orthostatic hypotension in ambulatory patients.

Hepatotoxicity

Precaution should be taken in patients with liver disease. Hepatotoxicity and severe hepatic failure occurred in chronic alcoholics following therapeutic doses.

PRECAUTIONS

General

Opioid analgesics should be used with caution when combined with CNS depressant drugs, and should be reserved for cases where the benefits of opioid analgesia outweigh the known risks of respiratory depression, altered mental state, and postural hypotension.

Acute Abdominal Conditions

The administration of ratio-Oxycocet (Acetaminophen,Oxycodone Hydrochloride) (oxycodone and acetaminophen ) (Oxycodone and Acetaminophen) or other opioids may obscure the diagnosis or clinical course in patients with acute abdominal conditions.

ratio-Oxycocet (Acetaminophen,Oxycodone Hydrochloride) (oxycodone and acetaminophen ) should be given with caution to patients with CNS depression, elderly or debilitated patients, patients with severe impairment of hepatic, pulmonary, or renal function, hypothyroidism, Addison's disease, prostatic hypertrophy, urethral stricture, acute alcoholism, delirium tremens, kyphoscoliosis with respiratory depression, myxedema, and toxic psychosis.

ratio-Oxycocet (Acetaminophen,Oxycodone Hydrochloride) (oxycodone and acetaminophen ) may obscure the diagnosis or clinical course in patients with acute abdominal conditions. Oxycodone may aggravate convulsions in patients with convulsive disorders, and all opioids may induce or aggravate seizures in some clinical settings.

Following administration of ratio-Oxycocet (Acetaminophen,Oxycodone Hydrochloride) (oxycodone and acetaminophen ) , anaphylactic reactions have been reported in patients with a known hypersensitivity to codeine, a compound with a structure similar to morphine and oxycodone. The frequency of this possible cross-sensitivity is unknown.

Interactions with Other CNS Depressants

Patients receiving other opioid analgesics, general anesthetics, phenothiazines, other tranquilizers, centrally-acting anti-emetics, sedative-hypnotics or other CNS depressants (including alcohol) concomitantly with ratio-Oxycocet (Acetaminophen,Oxycodone Hydrochloride) (oxycodone and acetaminophen ) may exhibit an additive CNS depression. When such combined therapy is contemplated, the dose of one or both agents should be reduced.

Interactions with Mixed Agonist/Antagonist Opioid Analgesics

Agonist/antagonist analgesics (i.e., pentazocine, nalbuphine, and butorphanol) should be administered with caution to a patient who has received or is receiving a course of therapy with a pure opioid agonist analgesic such as oxycodone. In this situation, mixed agonist/antagonist analgesics may reduce the analgesic effect of oxycodone and/or may precipitate withdrawal symptoms in these patients.

Ambulatory Surgery and Postoperative Use

Oxycodone and other morphine-like opioids have been shown to decrease bowel motility. Ileus is a common postoperative complication, especially after intra-abdominal surgery with use of opioid analgesia. Caution should be taken to monitor for decreased bowel motility in postoperative patients receiving opioids. Standard supportive therapy should be implemented.

Use in Pancreatic/Biliary Tract Disease

Oxycodone may cause spasm of the Sphincter of Oddi and should be used with caution in patients with biliary tract disease, including acute pancreatitis. Opioids like oxycodone may cause increases in the serum amylase level.

Tolerance and Physical Dependence

Tolerance is the need for increasing doses of opioids to maintain a defined effect such as analgesia (in the absence of disease progression or other external factors). Physical dependence is manifested by withdrawal symptoms after abrupt discontinuation of a drug or upon administration of an antagonist. Physical dependence and tolerance are not unusual during chronic opioid therapy.

The opioid abstinence or withdrawal syndrome is characterized by some or all of the following: restlessness, lacrimation, rhinorrhea, yawning, perspiration, chills, myalgia, and mydriasis. Other symptoms also may develop, including: irritability, anxiety, backache, joint pain, weakness, abdominal cramps, insomnia, nausea, anorexia, vomiting, diarrhea, or increased blood pressure, respiratory rate, or heart rate.

In general, opioids should not be abruptly discontinued (see DOSAGE AND ADMINISTRATION: Cessation of Therapy).

Laboratory Tests

Although oxycodone may cross-react with some drug urine tests, no available studies were found which determined the duration of detectability of oxycodone in urine drug screens. However, based on pharmacokinetic data, the approximate duration of detectability for a single dose of oxycodone is roughly estimated to be one to two days following drug exposure.

Urine testing for opiates may be performed to determine illicit drug use and for medical reasons such as evaluation of patients with altered states of consciousness or monitoring efficacy of drug rehabilitation efforts. The preliminary identification of opiates in urine involves the use of an immunoassay screening and thin-layer chromatography (TLC). Gas chromatography/mass spectrometry (GC/MS) may be utilized as a third-stage identification step in the medical investigational sequence for opiate testing after immunoassay and TLC. The identities of 6-keto opiates (e.g., oxycodone) can further be differentiated by the analysis of their methoximetrimethylsilyl (MO-TMS) derivative.

Carcinogenesis, Mutagenesis, Impairment of Fertility

Carcinogenesis

Animal studies to evaluate the carcinogenic potential of oxycodone and acetaminophen have not been performed.

Mutagenesis

The combination of oxycodone and acetaminophen has not been evaluated for mutagenicity. Oxycodone alone was negative in a bacterial reverse mutation assay (Ames), an in vitro chromosome aberration assay with human lymphocytes without metabolic activation and an in vivo mouse micronucleus assay. Oxycodone was clastogenic in the human lymphocyte chromosomal assay in the presence of metabolic activation and in the mouse lymphoma assay with or without metabolic activation.

Fertility

Animal studies to evaluate the effects of oxycodone on fertility have not been performed.

Pregnancy

Teratogenic Effects

Pregnancy Category C.: Animal reproductive studies have not been conducted with ratio-Oxycocet (Acetaminophen,Oxycodone Hydrochloride) (oxycodone and acetaminophen ). It is also not known whether ratio-Oxycocet (Acetaminophen,Oxycodone Hydrochloride) (oxycodone and acetaminophen ) can cause fetal harm when administered to a pregnant woman or can affect reproductive capacity. ratio-Oxycocet (Acetaminophen,Oxycodone Hydrochloride) (oxycodone and acetaminophen ) should not be given to a pregnant woman unless in the judgment of the physician, the potential benefits outweigh the possible hazards.

Nonteratogenic Effects

Opioids can cross the placental barrier and have the potential to cause neonatal respiratory depression. Opioid use during pregnancy may result in a physically drug-dependent fetus. After birth, the neonate may suffer severe withdrawal symptoms.

Labor and Delivery

ratio-Oxycocet (Acetaminophen,Oxycodone Hydrochloride) (oxycodone and acetaminophen ) is not recommended for use in women during and immediately prior to labor and delivery due to its potential effects on respiratory function in the newborn.

Nursing Mothers

Ordinarily, nursing should not be undertaken while a patient is receiving ratio-Oxycocet (Acetaminophen,Oxycodone Hydrochloride) (oxycodone and acetaminophen ) because of the possibility of sedation and/or respiratory depression in the infant. Oxycodone is excreted in breast milk in low concentrations, and there have been rare reports of somnolence and lethargy in babies of nursing mothers taking an oxycodone/acetaminophen product. Acetaminophen is also excreted in breast milk in low concentrations.

Pediatric Use

Safety and effectiveness in pediatric patients have not been established.

Geriatric Use

Special precaution should be given when determining the dosing amount and frequency of ratio-Oxycocet (Acetaminophen,Oxycodone Hydrochloride) (oxycodone and acetaminophen ) for geriatric patients, since clearance of oxycodone may be slightly reduced in this patient population when compared to younger patients.

Hepatic Impairment

In a pharmacokinetic study of oxycodone in patients with end-stage liver disease, oxycodone plasma clearance decreased and the elimination half-life increased. Care should be exercised when oxycodone is used in patients with hepatic impairment.

Renal Impairment

In a study of patients with end stage renal impairment, mean elimination half-life was prolonged in uremic patients due to increased volume of distribution and reduced clearance. Oxycodone should be used with caution in patients with renal impairment.

WARNINGS

Contains sodium metabisulfite, a sulfite that may cause allergic-type reactions including anaphylactic symptoms and life-threatening or less severe asthmatic episodes in certain susceptible people. The overall prevalence of sulfite sensitivity in the general population is unknown and probably low. Sulfite sensitivity is seen more frequently in asthmatic than in nonasthmatic people.

Drug Dependence

Oxycodone can produce drug dependence of the morphine type and, therefore, has the potential for being abused. Psychic dependence, physical dependence and tolerance may develop upon repeated administration of TYLOX (oxycodone and acetaminophen capsules) (oxycodone and acetaminophen capsules), and it should be prescribed and administered with the same degree of caution appropriate to the use of other oral narcotic-containing medications. Like other narcotic-containing medications, TYLOX (oxycodone and acetaminophen capsules) is subject to the Federal Control Substances Act (Schedule II).

PRECAUTIONS

General

Head Injury and Increased Intracranial Pressure: The respiratory depressant effects of narcotics and their capacity to elevate cerebrospinal fluid pressure may be markedly exaggerated in the presence of head injury, other intracranial lesions or a pre-existing increase in intracranial pressure. Furthermore, narcotics produce adverse reactions which may obscure the clinical course of patients with head injuries.

Acute Abdominal Conditions: The administration of TYLOX (oxycodone and acetaminophen capsules) (oxycodone and acetaminophen capsules) or other narcotics may obscure the diagnosis or clinical course in patients with acute abdominal conditions.

Special Risk Patients: TYLOX (oxycodone and acetaminophen capsules) should be given with caution to certain patients such as the elderly or debilitated, and those with severe impairment of hepatic or renal function, hypothyroidism, Addison's disease, and prostatic hypertrophy or urethral stricture.

Usage in Pregnancy

Pregnancy Category C. Animal reproductive studies have not been conducted with TYLOX (oxycodone and acetaminophen capsules). It is also not known whether TYLOX (oxycodone and acetaminophen capsules) can cause fetal harm when administered to a pregnant woman or can affect reproductive capacity. TYLOX (oxycodone and acetaminophen capsules) should not be given to a pregnant woman unless in the judgment of the physician, the potential benefits outweigh the possible hazards.

Nonteratogenic Effects: Use of narcotics during pregnancy may produce physical dependence in the neonate.

Labor and Delivery

As with all narcotics, administration of TYLOX (oxycodone and acetaminophen capsules) to the mother shortly before delivery may result in some degree of respiratory depression in the newborn and the mother, especially if higher doses are used.

Nursing Mothers

It is not known whether the components of TYLOX (oxycodone and acetaminophen capsules) are excreted in human milk. Because many drugs are excreted in human milk, caution should be exercised when TYLOX (oxycodone and acetaminophen capsules) is administered to a nursing woman.

Pediatric Use

Safety and effectiveness in children have not been established.

The following treatment-emergent adverse reactions are discussed in more detail in other sections of the labeling:

• Respiratory Depression
• Hepatotoxicity
• Use With Other Acetaminophen-containing Products
• Interactions with Other CNS Depressants

Clinical Studies Experience

Because clinical studies are conducted under widely varying conditions, adverse reaction rates observed in the clinical studies of a drug cannot be directly compared to rates in the clinical studies of another drug and may not reflect the rates observed in clinical practice.

In safety data from two Phase 3 (one placebo-controlled, one open-label) trials where multiple doses of ratio-Oxycocet (Acetaminophen,Oxycodone Hydrochloride) were administered for up to 42 days, the most common adverse reactions (reported by ≥ 10% in any ratio-Oxycocet (Acetaminophen,Oxycodone Hydrochloride) dose group) were: nausea, dizziness and vomiting. The most common reasons for discontinuation due to AEs in these 2 studies (reported by ≥ 1% in any ratio-Oxycocet (Acetaminophen,Oxycodone Hydrochloride) dose group) were vomiting (4.8%) and nausea (4.1%); there were no reports of these adverse reactions in the placebo-treated patients.

A total of 1028 subjects in 14 clinical studies were treated with ratio-Oxycocet (Acetaminophen,Oxycodone Hydrochloride) during the clinical development program, including 892 subjects treated with 15 mg oxycodone and 650 mg acetaminophen. This dosage regimen of ratio-Oxycocet (Acetaminophen,Oxycodone Hydrochloride) was administered to 607 patients in two Phase 3 studies (one placebo-controlled and one open-label).

In a placebo-controlled post-bunionectomy acute pain trial, 329 patients were dosed with 15 mg oxycodone and 650 mg acetaminophen ratio-Oxycocet (Acetaminophen,Oxycodone Hydrochloride) or placebo orally every 12 hours, for approximately 48 hours (blinded period). Table 1 lists the adverse reactions reported by ≥ 1% of ratio-Oxycocet (Acetaminophen,Oxycodone Hydrochloride)-treated patients and more frequently in ratio-Oxycocet (Acetaminophen,Oxycodone Hydrochloride)treated patients compared with placebo.

Table 1: Treatment-Emergent Adverse Reactions* Reported by ≥ 1% of ratio-Oxycocet (Acetaminophen,Oxycodone Hydrochloride)-Treated Patients and More Frequently than Placebo in ratio-Oxycocet (Acetaminophen,Oxycodone Hydrochloride)-Treated Patients with Postoperative Bunionectomy Pain (blinded period)

Other Adverse Reactions Observed During The Premarketing Evaluation Of ratio-Oxycocet (Acetaminophen,Oxycodone Hydrochloride)

The following adverse drug reactions not listed above occurred in ≥ 1% of ratio-Oxycocet (Acetaminophen,Oxycodone Hydrochloride)-treated patients in the pooled safety data from two Phase 3 studies (including a placebo-controlled and an open-label non-controlled safety study) where multiple-doses of ratio-Oxycocet (Acetaminophen,Oxycodone Hydrochloride) were administered every 12 hours for up to 42 days:

Gastrointestinal disorders: dry mouth, dyspepsia, diarrhea

General disorders and administration site conditions: fatigue

Investigations: hepatic enzyme increased

Psychiatric disorders: insomnia

Respiratory, thoracic and mediastinal disorders: cough

The following adverse drug reactions occurred in < 1% of ratio-Oxycocet (Acetaminophen,Oxycodone Hydrochloride)-treated patients in the pooled safety data from the two Phase 3 studies described above:

Cardiac disorders: palpitations

Eye and ear disorders: tinnitus, vision blurred

Gastrointestinal disorders: abdominal discomfort, abdominal pain, esophageal spasm

General disorders and administration site conditions: asthenia, chest discomfort, chills, contusion, fall, feeling jittery, malaise, non-cardiac chest pain, thirst

Immune system disorders: hypersensitivity

Investigations: alanine aminotransferase increased, aspartate aminotransferase increased, blood lactate dehydrogenase increased, blood pressure increased, gamma-glutamyltransferase increased, liver functional test abnormal

Metabolic and nutritional: decreased appetite

Musculoskeletal and connective tissue disorders: arthralgia, musculoskeletal stiffness

Nervous system disorders: cognitive disorder, memory impairment, migraine, myoclonus, paraesthesia, sedation, tremor

Psychiatric disorders: anxiety, confusional state, disorientation, euphoric mood, mood altered, sleep disorder, withdrawal syndrome

Renal and urinary disorders: urine flow decreased

Respiratory, thoracic and mediastinal disorders: dyspnea, hiccups, hypopnea, oropharyngeal pain, throat irritation

Skin and subcutaneous tissue disorders: dermatitis, ecchymosis, hyperhidrosis, urticaria

Vascular disorders: flushing, hypertension

Serious adverse reactions that may be associated with ratio-Oxycocet (Acetaminophen,Oxycodone Hydrochloride) (oxycodone and acetaminophen ) use include respiratory depression, apnea, respiratory arrest, circulatory depression, hypotension, and shock (see OVERDOSAGE).

The most frequently observed non-serious adverse reactions include lightheadedness, dizziness, drowsiness or sedation, nausea, and vomiting. These effects seem to be more prominent in ambulatory than in nonambulatory patients, and some of these adverse reactions may be alleviated if the patient lies down. Other adverse reactions include euphoria, dysphoria, constipation, and pruritus.

Hypersensitivity reactions may include: Skin eruptions, urticarial, erythematous skin reactions. Hematologic reactions may include: Thrombocytopenia, neutropenia, pancytopenia, hemolytic anemia. Rare cases of agranulocytosis has likewise been associated with acetaminophen use. In high doses, the most serious adverse effect is a dose-dependent, potentially fatal hepatic necrosis. Renal tubular necrosis and hypoglycemic coma also may occur.

Other adverse reactions obtained from postmarketing experiences with ratio-Oxycocet (Acetaminophen,Oxycodone Hydrochloride) (oxycodone and acetaminophen ) are listed by organ system and in decreasing order of severity and/or frequency as follows:

Body as a Whole

Anaphylactoid reaction, allergic reaction, malaise, asthenia, fatigue, chest pain, fever, hypothermia, thirst, headache, increased sweating, accidental overdose, non-accidental overdose

Cardiovascular

Hypotension, hypertension, tachycardia, orthostatic hypotension, bradycardia, palpitations, dysrhythmias

Central and Peripheral Nervous System

Stupor, tremor, paraesthesia, hypoaesthesia, lethargy, seizures, anxiety, mental impairment, agitation, cerebral edema, confusion, dizziness

Fluid and Electrolyte

Dehydration, hyperkalemia, metabolic acidosis, respiratory alkalosis

Gastrointestinal

Dyspepsia, taste disturbances, abdominal pain, abdominal distention, sweating increased, diarrhea, dry mouth, flatulence, gastro-intestinal disorder, nausea, vomiting, pancreatitis, intestinal obstruction, ileus

Hepatic

Transient elevations of hepatic enzymes, increase in bilirubin, hepatitis, hepatic failure, jaundice, hepatotoxicity, hepatic disorder

Hearing and Vestibular

Hearing loss, tinnitus

Hematologic

Thrombocytopenia

Hypersensitivity

Acute anaphylaxis, angioedema, asthma, bronchospasm, laryngeal edema, urticaria, anaphylactoid reaction

Metabolic and Nutritional

Hypoglycemia, hyperglycemia, acidosis, alkalosis

Musculoskeletal

Myalgia, rhabdomyolysis

Ocular

Miosis, visual disturbances, red eye

Psychiatric

Drug dependence, drug abuse, insomnia, confusion, anxiety, agitation, depressed level of consciousness, nervousness, hallucination, somnolence, depression, suicide

Respiratory System

Bronchospasm, dyspnea, hyperpnea, pulmonary edema, tachypnea, aspiration, hypoventilation, laryngeal edema

Skin and Appendages

Erythema, urticaria, rash, flushing

Urogenital

Interstitial nephritis, papillary necrosis, proteinuria, renal insufficiency and failure, urinary retention

Drug Abuse And Dependence

ratio-Oxycocet (Acetaminophen,Oxycodone Hydrochloride) (oxycodone and acetaminophen ) is a Schedule II controlled substance. Oxycodone is a mu-agonist opioid with an abuse liability similar to morphine. Oxycodone, like morphine and other opioids used in analgesia, can be abused and is subject to criminal diversion.

Drug addiction is defined as an abnormal, compulsive use, use for non-medical purposes of a substance despite physical, psychological, occupational or interpersonal difficulties resulting from such use, and continued use despite harm or risk of harm. Drug addiction is a treatable disease, utilizing a multidisciplinary approach, but relapse is common. Opioid addiction is relatively rare in patients with chronic pain but may be more common in individuals who have a past history of alcohol or substance abuse or dependence. Pseudoaddiction refers to pain relief seeking behavior of patients whose pain is poorly managed. It is considered an iatrogenic effect of ineffective pain management. The health care provider must assess continuously the psychological and clinical condition of a pain patient in order to distinguish addiction from pseudoaddiction and thus, be able to treat the pain adequately.

Physical dependence on a prescribed medication does not signify addiction. Physical dependence involves the occurrence of a withdrawal syndrome when there is sudden reduction or cessation in drug use or if an opiate antagonist is administered. Physical dependence can be detected after a few days of opioid therapy. However, clinically significant physical dependence is only seen after several weeks of relatively high dosage therapy. In this case, abrupt discontinuation of the opioid may result in a withdrawal syndrome. If the discontinuation of opioids is therapeutically indicated, gradual tapering of the drug over a 2-week period will prevent withdrawal symptoms. The severity of the withdrawal syndrome depends primarily on the daily dosage of the opioid, the duration of therapy and medical status of the individual.

The withdrawal syndrome of oxycodone is similar to that of morphine. This syndrome is characterized by yawning, anxiety, increased heart rate and blood pressure, restlessness, nervousness, muscle aches, tremor, irritability, chills alternating with hot flashes, salivation, anorexia, severe sneezing, lacrimation, rhinorrhea, dilated pupils, diaphoresis, piloerection, nausea, vomiting, abdominal cramps, diarrhea and insomnia, and pronounced weakness and depression.

“Drug-seeking” behavior is very common in addicts and drug abusers. Drug-seeking tactics include emergency calls or visits near the end of office hours, refusal to undergo appropriate examination, testing or referral, repeated “loss” of prescriptions, tampering with prescriptions and reluctance to provide prior medical records or contact information for other treating physician(s). “Doctor Shopping” to obtain additional prescriptions is common among drug abusers and people suffering from untreated infection.

Abuse and addiction are separate and distinct from physical dependence and tolerance. Physicians should be aware that addiction may not be accompanied by concurrent tolerance and symptoms of physical dependence in all addicts. In addition, abuse of opioids can occur in the absence of true addiction and is characterized by misuse for non-medical purposes, often in combination with other psychoactive substances. Oxycodone, like other opioids, has been diverted for non-medical use. Careful record-keeping of prescribing information, including quantity, frequency, and renewal requests is strongly advised.

Proper assessment of the patient, proper prescribing practices, periodic re-evaluation of therapy, and proper dispensing and storage are appropriate measures that help to limit abuse of opioid drugs.

Like other opioid medications, ratio-Oxycocet (Acetaminophen,Oxycodone Hydrochloride) (oxycodone and acetaminophen ) is subject to the Federal Controlled Substances Act. After chronic use, ratio-Oxycocet (Acetaminophen,Oxycodone Hydrochloride) (oxycodone and acetaminophen ) should not be discontinued abruptly when it is thought that the patient has become physically dependent on oxycodone.

Interactions with Alcohol and Drugs of Abuse

Oxycodone may be expected to have additive effects when used in conjunction with alcohol, other opioids, or illicit drugs that cause central nervous system depression.

The most frequently observed adverse reactions include lightheadedness, dizziness, sedation, nausea and vomiting. These effects seem to be more prominent in ambulatory than in non-ambulatory patients, and some of these adverse reactions may be alleviated if the patient lies down.

Other adverse reactions include allergic reactions, euphoria, dysphoria, constipation, skin rash and pruritus. At higher doses, oxycodone has most of the disadvantages of morphine including respiratory depression.

Drug Abuse And Dependence

TYLOX (oxycodone and acetaminophen capsules) capsules are a Schedule II controlled substance.

Oxycodone can produce drug dependence and has the potential for being abused. (See WARNINGS)

Signs And Symptoms

Following an acute overdosage, toxicity may result from the oxycodone or the acetaminophen.

Oxycodone

Acute overdosage with opioids is often characterized by respiratory depression, somnolence progressing to stupor or coma, skeletal muscle flaccidity, cold and clammy skin, constricted pupils, and, sometimes, pulmonary edema, bradycardia, hypotension, and death. Marked mydriasis rather than miosis may be seen due to severe hypoxia in overdose situations.

Acetaminophen

In acetaminophen overdosage, dose-dependent potentially fatal hepatic necrosis is the most serious adverse effect. Renal tubular necrosis, hypoglycemic coma, and coagulation defects may also occur.

Early symptoms following a potentially hepatotoxic overdose may include: nausea, vomiting, diaphoresis, and general malaise. Clinical and laboratory evidence of hepatic toxicity may not be apparent until 48 to 72 hours post-ingestion.

Treatment

A single or multiple drug overdose with oxycodone and acetaminophen is a potentially lethal polydrug overdose, and consultation with a regional poison control center is recommended. Immediate treatment includes support of cardiorespiratory function and measures to reduce drug absorption. Oxygen, intravenous fluids, vasopressors, assisted ventilation, and other supportive measures should be employed as indicated.

Oxycodone

Primary attention should be given to the reestablishment of adequate respiratory exchange through provision of a patent airway and the institution of assisted or controlled ventilation. The opioid antagonist naloxone hydrochloride is a specific antidote against respiratory depression which may result from overdose or unusual sensitivity to opioids, including oxycodone. Since the duration of action of oxycodone may exceed that of the antagonist, the patient should be kept under continued surveillance, and repeated doses of the antagonist should be administered as needed to maintain adequate respiration.

Opioid antagonists should not be administered in the absence of clinically significant respiratory or circulatory depression. Administer opioid antagonists cautiously to persons who are known, or suspected to be, physically dependent on ratio-Oxycocet (Acetaminophen,Oxycodone Hydrochloride). In such cases, an abrupt or complete reversal of opioid effects may precipitate an acute abstinence syndrome. In an individual physically dependent on opioids, administration of the usual dose of the antagonist will precipitate an acute withdrawal syndrome. The severity of the withdrawal syndrome produced will depend on the degree of physical dependence and the dose of the antagonist administered. If a decision is made to treat serious respiratory depression in the physically dependent patient, administration of the agonist should be begun with care and by titration with smaller than usual doses of the agonist.

Acetaminophen

Gastric decontamination with activated charcoal should be administered just prior to N-acetylcysteine (NAC) to decrease systemic absorption if acetaminophen ingestion is known or suspected to have occurred within a few hours of presentation. Serum acetaminophen levels should be obtained immediately if the patient presents 4 hours or more after ingestion to assess potential risk of hepatotoxicity; acetaminophen levels drawn less than 4 hours post-ingestion may be misleading. To obtain the best possible outcome, NAC should be administered as soon as possible where impending or evolving liver injury is suspected. Intravenous NAC may be administered when circumstances preclude oral administration.

Vigorous supportive therapy is required in severe intoxication. Procedures to limit the continuing absorption of the drug must be readily performed since the hepatic injury is dose-dependent and occurs early in the course of intoxication.

Signs and Symptoms

Serious overdose with ratio-Oxycocet (Acetaminophen,Oxycodone Hydrochloride) (oxycodone and acetaminophen ) (Oxycodone and Acetaminophen) is characterized by signs and symptoms of opioid and acetaminophen overdose. Oxycodone overdosage can be manifested by respiratory depression (a decrease in respiratory rate and/or tidal volume, Cheyne-Stokes respiration, cyanosis), extreme somnolence progressing to stupor or coma, skeletal muscle flaccidity, cold and clammy skin, pupillary constriction (pupils may be dilated in the setting of hypoxia), and sometimes bradycardia and hypotension. In severe overdosage, apnea, circulatory collapse, cardiac arrest and death may occur.

In acute acetaminophen overdosage, dose-dependent, potentially fatal hepatic necrosis is the most serious adverse effect. Renal tubular necrosis, hypoglycemic coma and thrombocytopenia may also occur.

In adults, hepatic toxicity has rarely been reported with acute overdoses of less than 10 grams and fatalities with less than 15 grams. Plasma acetaminophen levels > 300 mcg/mL at 4 hours post-ingestion were associated with hepatic damage in 90% of patients; minimal hepatic damage is anticipated if plasma levels at 4 hours are < 120 mcg/mL or < 30 mcg/mL at 12 hours after ingestion.

Importantly, young children seem to be more resistant than adults to the hepatotoxic effect of an acetaminophen overdose. Despite this, the measures outlined below should be initiated in any adult or child suspected of having ingested an acetaminophen overdose.

Early symptoms following a potentially hepatotoxic overdose may include: nausea, vomiting, diaphoresis and general malaise. Clinical and laboratory evidence of hepatic toxicity may not be apparent until 48 to 72 hours post-ingestion.

Treatment

Primary attention should be given to the re-establishment of adequate respiratory exchange through provision of a patent airway and the institution of assisted or controlled ventilation. Supportive measures (including oxygen, intravenous fluids, and vasopressors) should be employed in the management of circulatory shock and pulmonary edema accompanying overdose as indicated. Cardiac arrest or arrhythmias may require cardiac massage or defibrillation.

The opioid antagonist naloxone hydrochloride is a specific antidote against respiratory depression which may result from overdosage or unusual sensitivity to opioids including oxycodone. Therefore, an appropriate dose of naloxone hydrochloride should be administered (usual initial adult dose 0.4 mg to 2 mg) preferably by the intravenous route, simultaneously with efforts at respiratory resuscitation. Since the duration of action of oxycodone may exceed that of the antagonist, the patient should be kept under continued surveillance and repeated doses of the antagonist should be administered as needed to maintain adequate respiration. Opioid antagonists should not be administered in the absence of clinically significant respiratory or circulatory depression secondary to oxycodone overdose. In patients who are physically dependent on any opioid agonist including oxycodone, an abrupt or complete reversal of opioid effects may precipitate an acute abstinence syndrome. The severity of the withdrawal syndrome produced will depend on the degree of physical dependence and the dose of the antagonist administered. Please see the prescribing information for the specific opioid antagonist for details of their proper use.

Gastric emptying and/or lavage may be useful in removing unabsorbed drug. This procedure is recommended as soon as possible after ingestion, even if the patient has vomited spontaneously. After lavage and/or emesis, administration of activated charcoal, as a slurry, is beneficial, if less than three hours have passed since ingestion. Charcoal adsorption should not be employed prior to lavage and emesis.

If an acetaminophen overdose is suspected, the stomach should be promptly emptied by lavage. A serum acetaminophen assay should be obtained as soon as possible, but no sooner than 4 hours following ingestion. Liver function studies should be obtained initially and repeated at 24-hour intervals. The antidote N-acetylcysteine (NAC) should be administered as early as possible, preferably within 16 hours of the overdose ingestion, but in any case within 24 hours. As a guide to treatment of acute ingestion, the acetaminophen level can be plotted against time since ingestion on a nomogram (Rumack- Matthew). The upper toxic line on the nomogram is equivalent to 200 mcg/mL at 4 hours while the lower line is equivalent to 50 mcg/mL at 12 hours. If serum level is above the lower line, and entire course of N-acetylcysteine treatment should be instituted. NAC therapy should be withheld if the acetaminophen level is below the lower line.

The toxicity of oxycodone and acetaminophen in combination is unknown.

Acetaminophen

Signs and Symptoms: In acute acetaminophen overdosage, dose-dependent potentially fatal hepatic necrosis is the most serious adverse effect. Renal tubular necrosis, hypoglycemic coma and thrombocytopenia may also occur.

In adults, hepatic toxicity has rarely been reported with acute overdoses of less than 10 grams and fatalities with less than 15 grams. Importantly, young children seem to be more resistant than adults to the hepatotoxic effect of an acetaminophen overdose. Despite this, the measures outlined below should be initiated in any adult or child suspected of having ingested an acetaminophen overdose.

Early symptoms following a potentially hepatotoxic overdose may include: nausea, vomiting, diaphoresis and general malaise. Clinical and laboratory evidence of hepatic toxicity may not be apparent until 48 to 72 hours post-ingestion.

Treatment: The stomach should be emptied promptly by lavage or by induction of emesis with syrup of ipecac. Patients' estimates of the quantity of a drug ingested are notoriously unreliable. Therefore, if an acetaminophen overdose is suspected, a serum acetaminophen assay should be obtained as early as possible, but no sooner than four hours following ingestion. Liver function studies should be obtained initially and repeated at 24-hour intervals.

The antidote, N-acetylcysteine, should be administered as early as possible, and within 16 hours of the overdose ingestion for optimal results. Following recovery, there are no residual, structural, or functional hepatic abnormalities.

Oxycodone

Signs and Symptoms: Serious overdosage with oxycodone is characterized by respiratory depression (a decrease in respiratory rate and/or tidal volume, Cheyne-Stokes respiration, cyanosis), extreme somnolence progressing to stupor or coma, skeletal muscle flaccidity, cold and clammy skin, and sometimes bradycardia and hypotension. In severe overdosage, apnea, circulatory collapse, cardiac arrest and death may occur.

Treatment: Primary attention should be given to the reestablishment of adequate respiratory exchange through provision of a patent airway and the institution of assisted or controlled ventilation. The narcotic antagonist naloxone hydrochloride is a specific antidote against respiratory depression which may result from overdosage or unusual sensitivity to narcotics, including oxycodone. Therefore, an appropriate dose of naloxone hydrochloride (usual initial adult dose 0.4 mg to 2 mg) should be administered preferably by the intravenous route and simultaneously with efforts at respiratory resuscitation (see package insert). Since the duration of action of oxycodone may exceed that of the antagonist, the patient should be kept under continued surveillance and repeated doses of the antagonist should be administered as needed to maintain adequate respiration.

An antagonist should not be administered in the absence of clinically significant respiratory or cardiovascular depression. Oxygen, intravenous fluids, vasopressors and other supportive measures should be employed as indicated.

Gastric emptying may be useful in removing unabsorbed drug.

ratio-Oxycocet (Acetaminophen,Oxycodone Hydrochloride) is an extended-release bilayer formulation of oxycodone and acetaminophen (immediate- and extended-release layers) which is not interchangeable with other oxycodone/acetaminophen products because of differing pharmacokinetic profiles that affect the frequency of administration. The activity of oxycodone hydrochloride is primarily due to the parent drug oxycodone.

Absorption

The oral bioavailability of oxycodone is 60 to 87%. Bioavailability (dose-normalized AUC and Cmax) of oxycodone and acetaminophen following single- and multiple-doses of ratio-Oxycocet (Acetaminophen,Oxycodone Hydrochloride) tablets is comparable to immediate-release products containing oxycodone or acetaminophen.

Oxycodone plasma concentrations from this bilayer product are detectable within 30 minutes and reach a maximum concentration (Cmax) in 3 to 4 hours after ratio-Oxycocet (Acetaminophen,Oxycodone Hydrochloride) administration. Maximum plasma concentrations of acetaminophen occur in 0.75 to 1 hour after ratio-Oxycocet (Acetaminophen,Oxycodone Hydrochloride) administration.

Steady-state plasma concentrations of oxycodone and acetaminophen are achieved within 24 hours of initiation of dosing of XARTEMIS XR (prior to the third dose of two ratio-Oxycocet (Acetaminophen,Oxycodone Hydrochloride) tablets administered every 12 hours). ratio-Oxycocet (Acetaminophen,Oxycodone Hydrochloride) produces steady-state maximum plasma concentrations of oxycodone that are greater than those following the first dose, while concentrations of acetaminophen are comparable to the first dose (Table 2).

Table 2: Mean (SD) Pharmacokinetics of ratio-Oxycocet (Acetaminophen,Oxycodone Hydrochloride) (two 7.5 mg oxycodone and 325 mg acetaminophen extended-release tablets; after a single dose and multiple doses every 12 hours for 4.5 days)

Food Effect

When administered with a high- or low-fat meal, median Tmax values of oxycodone were delayed by 2 hours and 1 hour, respectively. Mean AUC values are increased by 15 to 16% and peak concentrations are 12 to 25% higher for oxycodone. Food delayed median acetaminophen Tmax by 1.5 hours. There is no change in mean acetaminophen AUC values and peak concentrations are 23 to 24% lower with food. ratio-Oxycocet (Acetaminophen,Oxycodone Hydrochloride) may be administered with or without food.

Distribution

Following intravenous administration, the volume of distribution (Vss) for oxycodone was 2.6 L/kg. Oxycodone was approximately 45% bound to plasma protein at 37°C and a pH of 7.4. Oxycodone has been found in breast milk.

Acetaminophen appears to be widely distributed throughout most body tissues except fat. Its apparent volume of distribution is about 0.9 L/kg. A relative small portion (~20%) of acetaminophen is bound to plasma protein.

Metabolism

Oxycodone hydrochloride is extensively metabolized to noroxycodone, oxymorphone, and their glucuronides. The major circulating metabolite is noroxycodone with an AUC ratio of 0.6 relative to that of oxycodone. Oxymorphone is present in the plasma only in low concentrations. The analgesic activity profile of other metabolites is not known at present.

The formation of oxymorphone, but not noroxycodone, is mediated by CYP2D6 and as such its formation can, in theory, be affected by other drugs.

Acetaminophen is primarily metabolized in the liver by first-order kinetics and involves three principal separate pathways:

1. conjugation with glucuronide;
2. conjugation with sulfate; and
3. oxidation via the cytochrome, P450-dependent, mixed-function oxidase enzyme pathway to form a reactive intermediate metabolite, which conjugates with glutathione and is then further metabolized to form cysteine and mercapturic acid conjugates.

The principal cytochrome P450 isoenzyme involved appears to be CYP2E1, with CYP1A2 and CYP3A4 as additional pathways.

In adults, the majority of acetaminophen is conjugated with glucuronic acid and, to a lesser extent, with sulfate. These glucuronide-, sulfate-, and glutathione-derived metabolites lack biologic activity. In premature infants, newborns, and young infants, the sulfate conjugate predominates.

Elimination

Oxycodone and its metabolites are eliminated primarily via the kidney. The amounts measured in the urine have been reported as follows: free oxycodone up to 19%; conjugated oxycodone up to 50%; free oxymorphone 0%; and conjugated oxymorphone ≤ 14%. Both free and conjugated noroxycodone have been found in urine but not quantified. The total plasma clearance was 0.8 L/min for adults. Apparent elimination half-life (mean ± SD) of oxycodone following administration of ratio-Oxycocet (Acetaminophen,Oxycodone Hydrochloride) was 4.5 ± 0.6 hours as compared to 3.9 ± 0.3 hours for immediate-release oxycodone.

Acetaminophen is eliminated from the body primarily by formation of glucuronide and sulfate conjugates in a dose-dependent manner. Less than 9% of acetaminophen is excreted unchanged in urine. Following administration of ratio-Oxycocet (Acetaminophen,Oxycodone Hydrochloride), the apparent elimination half-life is 5.8 ± 2.1 hours as compared to 4.1 ± 1.1 hours for immediate-release acetaminophen.

Absorption and Distribution

The mean absolute oral bioavailability of oxycodone in cancer patients was reported to be about 87%. Oxycodone has been shown to be 45% bound to human plasma proteins in vitro. The volume of distribution after intravenous administration is 211.9 ±186.6 L.

Absorption of acetaminophen is rapid and almost complete from the GI tract after oral administration. With overdosage, absorption is complete in 4 hours. Acetaminophen is relatively uniformly distributed throughout most body fluids. Binding of the drug to plasma proteins is variable; only 20% to 50% may be bound at the concentrations encountered during acute intoxication.

Metabolism and Elimination

A high portion of oxycodone is N-dealkylated to noroxycodone during first-pass metabolism. Oxymorphone, is formed by the O-demethylation of oxycodone. The metabolism of oxycodone to oxymorphone is catalyzed by CYP2D6. Free and conjugated noroxycodone, free and conjugated oxycodone, and oxymorphone are excreted in human urine following a single oral dose of oxycodone. Approximately 8% to 14% of the dose is excreted as free oxycodone over 24 hours after administration. Following a single, oral dose of oxycodone, the mean ± SD elimination half-life is 3.51 ± 1.43 hours.

Acetaminophen is metabolized in the liver via cytochrome P450 microsomal enzyme. About 80% to 85% of the acetaminophen in the body is conjugated principally with glucuronic acid and to a lesser extent with sulfuric acid and cysteine. After hepatic conjugation, 90% to 100% of the drug is recovered in the urine with in the first day.

About 4% of acetaminophen is metabolized via cytochrome P450 oxidase to a toxic metabolite which is further detoxified by conjugation with glutathione, present in a fixed amount. It is believed that the toxic metabolite NAPQI (N acetyl-p-benzoquinoneimine, N-acetylimidoquinone) is responsible for liver necrosis. High doses of acetaminophen may deplete the glutathione stores so that inactivation of the toxic metabolite is decreased. At high doses, the capacity of metabolic pathways for conjugation with glucuronic acid and sulfuric acid may be exceeded, resulting in increased metabolism of acetaminophen by alternate pathways.

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