Keppra XR

Dosage Forms And Strengths

KEPPRA XR tablets are white, oblong-shaped, film-coated extended-release tablets imprinted in red with “UCB 500XR” on one side and contain 500 mg levetiracetam.

KEPPRA XR tablets are white, oblong-shaped, film-coated extended-release tablets imprinted in red with “UCB 750XR” on one side and contain 750 mg levetiracetam.

Storage And Handling

KEPPRA XR 500 mg tablets are white, oblong-shaped, film-coated tablets imprinted with “UCB 500XR” in red on one side. They are supplied in white HDPE bottles containing 60 tablets (NDC 50474-598-66).

KEPPRA XR 750 mg tablets are white, oblong-shaped, film-coated tablets imprinted with “UCB 750XR” in red on one side. They are supplied in white HDPE bottles containing 60 tablets (NDC 50474-599-66).

Storage

Store at 25°C (77°F); excursions permitted to 15-30°C (59-86°F).

Distributed by UCB, Inc. Smyrna, GA 30080. Revised: Apr 2016

KEPPRA XR® is indicated as adjunctive therapy in the treatment of partial onset seizures in patients 12 years of age and older with epilepsy.

Recommended Dosing

KEPPRA XR is administered once daily. Initiate treatment with a dose of 1000 mg once daily. The once daily dosage may be adjusted in increments of 1000 mg every 2 weeks to a maximum recommended daily dose of 3000 mg/day.

Dosage Adjustment In Adult Patients With Renal Impairment

KEPPRA XR dosing must be individualized according to the patient's renal function status. Recommended dosage adjustments for adults are shown in Table 1. In order to calculate the dose recommended for patients with renal impairment, creatinine clearance adjusted for body surface area must be calculated. To do this, an estimate of the patient's creatinine clearance (CLcr) in mL/min must first be calculated using the following formula:

Then CLcr is adjusted for body surface area (BSA) as follows:

Table 1: Dosage Adjustment Regimen for Adult Patients with Renal Impairment

None.

WARNINGS

Included as part of the PRECAUTIONS section.

PRECAUTIONS

Behavioral Abnormalities And Psychotic Symptoms

KEPPRA XR may cause behavioral abnormalities and psychotic symptoms. Patients treated with KEPPRA XR should be monitored for psychiatric signs and symptoms.

Behavioral Abnormalities

KEPPRA XR Tablets

A total of 7% of KEPPRA XR-treated patients experienced non-psychotic behavioral disorders (reported as irritability and aggression) compared to 0% of placebo-treated patients. Irritability was reported in 7% of KEPPRA XR-treated patients. Aggression was reported in 1% of KEPPRA XR-treated patients.

No patient discontinued treatment or had a dose reduction as a result of these adverse reactions.

The number of patients exposed to KEPPRA XR was considerably smaller than the number of patients exposed to immediate-release KEPPRA tablets in controlled trials. Therefore, certain adverse reactions observed in the immediate-release KEPPRA controlled trials will likely occur in patients receiving KEPPRA XR.

Immediate-Release KEPPRA Tablets

A total of 13% of adult patients and 38% of pediatric patients (4 to 16 years of age) treated with immediate-release KEPPRA experienced non-psychotic behavioral symptoms (reported as aggression, agitation, anger, anxiety, apathy, depersonalization, depression, emotional lability, hostility, hyperkinesias, irritability, nervousness, neurosis, and personality disorder), compared to 6% and 19% of adult and pediatric patients on placebo. A randomized, double-blind, placebo-controlled study was performed to assess the neurocognitive and behavioral effects of immediate-release KEPPRA tablets as adjunctive therapy in pediatric patients (4 to 16 years of age). An exploratory analysis suggested a worsening in aggressive behavior in patients treated with immediate-release KEPPRA tablets in that study.

A total of 1.7% of adult patients treated with immediate-release KEPPRA discontinued treatment due to behavioral adverse reactions, compared to 0.2% of placebo-treated patients. The treatment dose was reduced in 0.8% of adult patients treated with immediate-release KEPPRA, compared to 0.5% of placebo-treated patients. Overall, 11% of pediatric patients treated with immediate-release KEPPRA experienced behavioral symptoms associated with discontinuation or dose reduction, compared to 6.2% of placebo-treated pediatric patients.

One percent of adult patients and 2% of pediatric patients (4 to 16 years of age) treated with immediate-release KEPPRA experienced psychotic symptoms, compared to 0.2% and 2%, respectively, in adult and placebo-treated pediatric patients. In the controlled study that assessed the neurocognitive and behavioral effects of immediate-release KEPPRA in pediatric patients 4 to 16 years of age, 1.6% KEPPRA-treated patients experienced paranoia, compared to no placebo-treated patients. There were 3.1% patients treated with immediate-release KEPPRA who experienced confusional state, compared to no placebo-treated patients.

Psychotic Symptoms

Immediate-Release KEPPRA tablets

One percent of KEPPRA-treated adult patients experienced psychotic symptoms compared to 0.2% of placebo-treated patients.

Two (0.3%) KEPPRA-treated adult patients were hospitalized and their treatment was discontinued due to psychosis. Both events, reported as psychosis, developed within the first week of treatment and resolved within 1 to 2 weeks following treatment discontinuation. There was no difference between drug and placebo-treated patients in the incidence of pediatric patients who discontinued treatment due to psychotic and non-psychotic adverse reactions.

Suicidal Behavior And Ideation

Antiepileptic drugs (AEDs), including KEPPRA XR, increase the risk of suicidal thoughts or behavior in patients taking these drugs for any indication. Patients treated with any AED for any indication should be monitored for the emergence or worsening of depression, suicidal thoughts or behavior, and/or any unusual changes in mood or behavior.

Pooled analyses of 199 placebo-controlled clinical trials (mono- and adjunctive therapy) of 11 different AEDs showed that patients randomized to one of the AEDs had approximately twice the risk (adjusted Relative Risk 1.8, 95% CI:1.2, 2.7) of suicidal thinking or behavior compared to patients randomized to placebo. In these trials, which had a median treatment duration of 12 weeks, the estimated incidence rate of suicidal behavior or ideation among 27,863 AED-treated patients was 0.43%, compared to 0.24% among 16,029 placebo-treated patients, representing an increase of approximately one case of suicidal thinking or behavior for every 530 patients treated. There were four suicides in drug-treated patients in the trials and none in placebo-treated patients, but the number is too small to allow any conclusion about drug effect on suicide.

The increased risk of suicidal thoughts or behavior with AEDs was observed as early as one week after starting drug treatment with AEDs and persisted for the duration of treatment assessed. Because most trials included in the analysis did not extend beyond 24 weeks, the risk of suicidal thoughts or behavior beyond 24 weeks could not be assessed.

The risk of suicidal thoughts or behavior was generally consistent among drugs in the data analyzed. The finding of increased risk with AEDs of varying mechanisms of action and across a range of indications suggests that the risk applies to all AEDs used for any indication. The risk did not vary substantially by age (5-100 years) in the clinical trials analyzed. Table 2 shows absolute and relative risk by indication for all evaluated AEDs.

Table 2: Risk by Indication for Antiepileptic Drugs in the Pooled Analysis

The relative risk for suicidal thoughts or behavior was higher in clinical trials for epilepsy than in clinical trials for psychiatric or other conditions, but the absolute risk differences were similar for the epilepsy and psychiatric indications.

Anyone considering prescribing KEPPRA XR or any other AED must balance the risk of suicidal thoughts or behavior with the risk of untreated illness. Epilepsy and many other illnesses for which AEDs are prescribed are themselves associated with morbidity and mortality and an increased risk of suicidal thoughts and behavior. Should suicidal thoughts and behavior emerge during treatment, the prescriber needs to consider whether the emergence of these symptoms in any given patient may be related to the illness being treated.

Patients, their caregivers, and families should be informed that AEDs increase the risk of suicidal thoughts and behavior and should be advised of the need to be alert for the emergence or worsening of the signs and symptoms of depression, any unusual changes in mood or behavior, or the emergence of suicidal thoughts, behavior, or thoughts about self-harm. Behaviors of concern should be reported immediately to healthcare providers.

Somnolence And Fatigue

KEPPRA XR may cause somnolence and fatigue. Patients should be monitored for these signs and symptoms and advised not to drive or operate machinery until they have gained sufficient experience on KEPPRA XR to gauge whether it adversely affects their ability to drive or operate machinery.

Somnolence

KEPPRA XR Tablets

In the KEPPRA XR double-blind, controlled trial in patients experiencing partial onset seizures, 8% of KEPPRA XR-treated patients experienced somnolence compared to 3% of placebo-treated patients.

No patient discontinued treatment or had a dose reduction as a result of these adverse reactions.

The number of patients exposed to KEPPRA XR was considerably smaller than the number of patients exposed to immediate-release KEPPRA tablets in controlled trials. Therefore, certain adverse reactions observed in the immediate-release KEPPRA controlled trials will likely occur in patients receiving KEPPRA XR.

Immediate-Release KEPPRA Tablets

In controlled trials of adult patients with epilepsy experiencing partial onset seizures, 15% of KEPPRA-treated patients reported somnolence, compared to 8% of placebo-treated patients. There was no clear dose response up to 3000 mg/day. In a study where there was no titration, about 45% of patients receiving 4000 mg/day reported somnolence. The somnolence was considered serious in 0.3% of the KEPPRA-treated patients, compared to 0% in the placebo group. About 3% of KEPPRA-treated patients discontinued treatment due to somnolence, compared to 0.7% of placebo-treated patients. In 1.4% of KEPPRA-treated patients and in 0.9% of placebo-treated patients the dose was reduced, while 0.3% of the treated patients were hospitalized due to somnolence.

Asthenia

Immediate-Release KEPPRA Tablets

In controlled trials of adult patients with epilepsy experiencing partial onset seizures, 15% of KEPPRA-treated patients reported asthenia, compared to 9% of placebo-treated patients. Treatment was discontinued due to asthenia in 0.8% of KEPPRA-treated patients as compared to 0.5% of placebo-treated patients. In 0.5% of KEPPRA-treated patients and in 0.2% of placebo-treated patients, the dose was reduced due to asthenia.

Somnolence and asthenia occurred most frequently within the first 4 weeks of treatment.

Serious Dermatological Reactions

Serious dermatological reactions, including Stevens-Johnson syndrome (SJS) and toxic epidermal necrolysis (TEN), have been reported in patients treated with levetiracetam. The median time of onset is reported to be 14 to 17 days, but cases have been reported at least four months after initiation of treatment. Recurrence of the serious skin reactions following rechallenge with levetiracetam has also been reported. KEPPRA XR should be discontinued at the first sign of a rash, unless the rash is clearly not drug-related. If signs or symptoms suggest SJS/TEN, use of this drug should not be resumed and alternative therapy should be considered.

Coordination Difficulties

Coordination difficulties were not observed in the KEPPRA XR controlled trial, however, the number of patients exposed to KEPPRA XR was considerably smaller than the number of patients exposed to immediate-release KEPPRA tablets in controlled trials. However, adverse reactions observed in the immediate-release KEPPRA controlled trials may also occur in patients receiving KEPPRA XR.

Immediate-Release KEPPRA Tablets

A total of 3.4% of adult KEPPRA-treated patients experienced coordination difficulties, (reported as either ataxia, abnormal gait, or incoordination) compared to 1.6% of placebo-treated patients. A total of 0.4% of patients in controlled trials discontinued KEPPRA treatment due to ataxia, compared to 0% of placebo-treated patients. In 0.7% of KEPPRA-treated patients and in 0.2% of placebo-treated patients, the dose was reduced due to coordination difficulties, while one of the KEPPRA-treated patients was hospitalized due to worsening of pre-existing ataxia. These events occurred most frequently within the first 4 weeks of treatment.

Patients should be monitored for these signs and symptoms and advised not to drive or operate machinery until they have gained sufficient experience on KEPPRA to gauge whether it could adversely affect their ability to drive or operate machinery.

Withdrawal Seizures

Antiepileptic drugs, including KEPPRA XR, should be withdrawn gradually to minimize the potential of increased seizure frequency.

Hematologic Abnormalities

KEPPRA XR can cause hematologic abnormalities. Hematologic abnormalities occurred in clinical trials and included decreases in red blood cell (RBC) counts, hemoglobin, and hematocrit, and increases in eosinophil counts. Decreased white blood cell (WBC) and neutrophil counts also occurred in clinical trials. Cases of agranulocytosis have been reported in the postmarketing setting.

In controlled trials of immediate-release KEPPRA tablets in patients experiencing partial onset seizures, minor, but statistically significant, decreases compared to placebo in total mean RBC count (0.03 x 10⁶/mm³), mean hemoglobin (0.09 g/dL), and mean hematocrit (0.38%), were seen in immediate-release KEPPRA-treated patients.

A total of 3.2% of KEPPRA-treated and 1.8% of placebo-treated patients had at least one possibly significant ( > 2.8 x 10⁹/L) decreased WBC, and 2.4% of KEPPRA-treated and 1.4% of placebo-traeted patients had at least one possibly significant ( > 1.0 x 10⁹/L) decreased neutrophil count. Of the KEPPRA-treated patients with a low neutrophil count, all but one rose towards or to baseline with continued treatment. No patient was discontinued secondary to low neutrophil counts.

In pediatric patients (4 to < 16 years of age), statistically significant decreases in WBC and neutrophil counts were seen in patients treated with immediate-release KEPPRA, as compared to placebo. The mean decreases from baseline in the immediate-release KEPPRA group were -0.4 × 10⁹/L and -0.3 × 10⁹/L, respectively, whereas there were small increases in the placebo group. A significant increase in mean relative lymphocyte counts was observed in 1.7% of patients treated with immediate-release KEPPRA compared to a decrease of 4% in patients on placebo.

In the controlled pediatric trial, a possibly clinically significant abnormal low WBC value was observed in 3% of patients treated with immediate-release KEPPRA, compared to no patients on placebo. However, there was no apparent difference between treatment groups with respect to neutrophil count. No patient was discontinued secondary to low WBC or neutrophil counts.

In the controlled pediatric cognitive and neuropsychological safety study, two subjects (6.1%) in the placebo group and 5 subjects (8.6%) in the immediate-release KEPPRA-treated group had high eosinophil count values that were possibly clinically significant ( ≥ 10% or ≥ 0.7X10⁹/L).

Seizure Control During Pregnancy

Physiological changes may gradually decrease plasma levels of levetiracetam throughout pregnancy. This decrease is more pronounced during the third trimester. It is recommended that patients be monitored carefully during pregnancy. Close monitoring should continue through the postpartum period especially if the dose was changed during pregnancy.

Patient Counseling Information

Advise the patient to read the FDA-approved patient labeling (Medication Guide).

Suicidal Behavior And Ideation

Counsel patients, their caregivers, and/or families that antiepileptic drugs (AEDs), including KEPPRA XR, may increase the risk of suicidal thoughts and behavior and advise patients to be alert for the emergence or worsening of symptoms of depression; unusual changes in mood or behavior; or suicidal thoughts, behavior, or thoughts about self-harm. Advise patients, their caregivers, and/or families to immediately report behaviors of concern to a healthcare provider.

Psychiatric Reactions And Changes In Behavior

Advise patients that KEPPRA XR may cause changes in behavior (e.g. irritability and aggression). In addition, patients should be advised that they may experience changes in behavior that have been seen with other formulations of KEPPRA, which include agitation, anger, anxiety, apathy, depression, hostility, and psychotic symptoms.

Effects On Driving Or Operating Machinery

Inform patients that KEPPRA XR may cause dizziness and somnolence. Inform patients not to drive or operate machinery until they have gained sufficient experience on KEPPRA XR to gauge whether it adversely affects their ability to drive or operate machinery.

Dermatological Adverse Reactions

Advise patients that serious dermatological adverse reactions have occurred in patients treated with levetiracetam and instruct them to call their physician immediately if a rash develops.

Dosing And Administration

Patients should be instructed to only take KEPPRA XR once daily and to swallow the tablets whole. They should not be chewed, broken, or crushed. Inform patients that they should not be concerned if they occasionally notice something that looks like swollen pieces of the original tablet in their stool.

Pregnancy

Advise patients to notify their healthcare provider if they become pregnant or intend to become pregnant during KEPPRA XR therapy. Encourage patients to enroll in the North American Antiepileptic Drug (NAAED) pregnancy registry if they become pregnant. This registry is collecting information about the safety of antiepileptic drugs during pregnancy. To enroll, patients can call the toll free number 1-888-233-2334.

Nonclinical Toxicology

Carcinogenesis, Mutagenesis, Impairment Of Fertility

Carcinogenesis

Rats were dosed with levetiracetam in the diet for 104 weeks at doses of 50, 300 and 1800 mg/kg/day. The highest dose is 6 times the maximum recommended daily human dose (MRHD) of 3000 mg on a mg/m² basis and it also provided systemic exposure (AUC) approximately 6 times that achieved in humans receiving the MRHD. There was no evidence of carcinogenicity. In mice, oral administration of levetiracetam for 80 weeks (doses up to 960 mg/kg/day) or 2 years (doses up to 4000 mg/kg/day, lowered to 3000 mg/kg/day after 45 weeks due to intolerability) was not associated with an increase in tumors. The highest dose tested in mice for 2 years (3000 mg/kg/day) is approximately 5 times the MRHD on a mg/m² basis.

Mutagenesis

Levetiracetam was not mutagenic in the Ames test or in mammalian cells in vitro in the Chinese hamster ovary/HGPRT locus assay. It was not clastogenic in an in vitro analysis of metaphase chromosomes obtained from Chinese hamster ovary cells or in an in vivo mouse micronucleus assay. The hydrolysis product and major human metabolite of levetiracetam (ucb L057) was not mutagenic in the Ames test or the in vitro mouse lymphoma assay.

Impairment Of Fertility

No adverse effects on male or female fertility or reproductive performance were observed in rats at oral doses up to 1800 mg/kg/day (6 times the maximum recommended human dose on a mg/m² or systemic exposure [AUC] basis).

Use In Specific Populations

Pregnancy

KEPPRA XR levels may decrease during pregnancy.

Pregnancy Category C

There are no adequate and well-controlled studies in pregnant women. In animal studies, levetiracetam produced evidence of developmental toxicity, including teratogenic effects, at doses similar to or greater than human therapeutic doses. KEPPRA XR should be used during pregnancy only if the potential benefit justifies the potential risk to the fetus.

Oral administration of levetiracetam to female rats throughout pregnancy and lactation led to increased incidences of minor fetal skeletal abnormalities and retarded offspring growth pre-and/or postnatally at doses ≥ 350 mg/kg/day (equivalent to the maximum recommended human dose of 3000 mg [MRHD] on a mg/m² basis) and with increased pup mortality and offspring behavioral alterations at a dose of 1800 mg/kg/day (6 times the MRHD on a mg/m² basis). The developmental no effect dose was 70 mg/kg/day (0.2 times the MRHD on a mg/m² basis). There was no overt maternal toxicity at the doses used in this study.

Oral administration of levetiracetam to pregnant rabbits during the period of organogenesis resulted in increased embryofetal mortality and increased incidences of minor fetal skeletal abnormalities at doses ≥ 600 mg/kg/day (4 times MRHD on a mg/m² basis) and in decreased fetal weights and increased incidences of fetal malformations at a dose of 1800 mg/kg/day (12 times the MRHD on a mg/m² basis). The developmental no effect dose was 200 mg/kg/day (equivalent to the MRHD on a mg/m² basis). Maternal toxicity was also observed at 1800 mg/kg/day.

When levetiracetam was administered orally to pregnant rats during the period of organogenesis, fetal weights were decreased and the incidence of fetal skeletal variations was increased at a dose of 3600 mg/kg/day (12 times the MRHD). 1200 mg/kg/day (4 times the MRHD) was a developmental no effect dose. There was no evidence of maternal toxicity in this study.

Treatment of rats with levetiracetam during the last third of gestation and throughout lactation produced no adverse developmental or maternal effects at oral doses of up to 1800 mg/kg/day (6 times the MRHD on a mg/m² basis).

Pregnancy Registry

To provide information regarding the effects of in utero exposure to KEPPRA XR, physicians are advised to recommend that pregnant patients taking KEPPRA XR enroll in the North American Antiepileptic Drug (NAAED) pregnancy registry. This can be done by calling the toll free number 1-888-233-2334, and must be done by the patients themselves. Information on the registry can also be found at the website http://www.aedpregnancyregistry.org/.

Labor And Delivery

The effect of KEPPRA XR on labor and delivery in humans is unknown.

Nursing Mothers

Levetiracetam is excreted in human milk. Because of the potential for serious adverse reactions in nursing infants from KEPPRA 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 in pediatric patients 12 years of age and older has been established based on pharmacokinetic data in adults and adolescents using KEPPRA XR and efficacy and safety data in controlled pediatric studies using immediate-release KEPPRA.

A 3-month, randomized, double-blind, placebo-controlled study was performed to assess the neurocognitive and behavioral effects of immediate-release KEPPRA as adjunctive therapy in 98 pediatric patients with inadequately controlled partial seizures, ages 4 to 16 years (KEPPRA N=64; placebo N=34). The target dose of immediate-release KEPPRA was 60 mg/kg/day. Neurocognitive effects were measured by the Leiter-R Attention and Memory (AM) Battery, which assesses various aspects of a child's memory and attention. Although no substantive differences were observed between the placebo- and KEPPRA-treated groups in the median change from baseline in this battery, the study was not adequate to assess formal statistical non-inferiority between the drug and placebo. The Achenbach Child Behavior Checklist (CBCL/6-18), a standardized validated tool used to assess a child's competencies and behavioral/emotional problems, was also assessed in this study. An analysis of the CBCL/6-18 indicated a worsening in aggressive behavior, one of the eight syndrome scores, in patients treated with KEPPRA.

Studies of levetiracetam in juvenile rats (dosing from day 4 through day 52 of age) and dogs (dosing from week 3 through week 7 of age) at doses of up to 1800 mg/kg/day (approximately 7 and 24 times, respectively, the maximum recommended pediatric dose of 60 mg/kg/day on a mg/m² basis) did not indicate a potential for age-specific toxicity.

Geriatric Use

There were insufficient numbers of elderly subjects in controlled trials of epilepsy to adequately assess the effectiveness of KEPPRA XR in these patients. It is expected that the safety of KEPPRA XR in elderly patients 65 and over would be comparable to the safety observed in clinical studies of immediate-release KEPPRA tablets.

There were 347 subjects in clinical studies of immediate-release KEPPRA that were 65 and over. No overall differences in safety were observed between these subjects and younger subjects. There were insufficient numbers of elderly subjects in controlled trials of epilepsy to adequately assess the effectiveness of immediate-release KEPPRA in these patients.

Levetiracetam is known to be substantially excreted by the kidney, and the risk of adverse reactions to this drug may be greater in patients with impaired renal function. Because elderly patients are more likely to have decreased renal function, care should be taken in dose selection, and it may be useful to monitor renal function.

Renal Impairment

The effect of KEPPRA XR on renally impaired patients was not assessed in the controlled study. However, it is expected that the effect on KEPPRA XR-treated patients would be similar to the effect seen in controlled studies of immediate-release KEPPRA tablets. Clearance of levetiracetam is decreased in patients with renal impairment and is correlated with creatinine clearance. Dose adjustment is recommended for patients with impaired renal function.

In vitro data on metabolic interactions indicate that levetiracetam is unlikely to produce, or be subject to, pharmacokinetic interactions. Levetiracetam and its major metabolite, at concentrations well above Cmax levels achieved within the therapeutic dose range, are neither inhibitors of, nor high affinity substrates for, human liver cytochrome P450 isoforms, epoxide hydrolase or UDPglucuronidation enzymes. In addition, levetiracetam does not affect the in vitro glucuronidation of valproic acid.

Potential pharmacokinetic interactions of or with levetiracetam were assessed in clinical pharmacokinetic studies (phenytoin, valproate, warfarin, digoxin, oral contraceptive, probenecid) and through pharmacokinetic screening with immediate-release KEPPRA tablets in the placebo-controlled clinical studies in epilepsy patients. The potential for drug interactions for KEPPRA XR is expected to be essentially the same as that with immediate-release KEPPRA tablets.

Phenytoin

Immediate-release KEPPRA tablets (3000 mg daily) had no effect on the pharmacokinetic disposition of phenytoin in patients with refractory epilepsy. Pharmacokinetics of levetiracetam were also not affected by phenytoin.

Valproate

Immediate-release KEPPRA tablets (1500 mg twice daily) did not alter the pharmacokinetics of valproate in healthy volunteers. Valproate 500 mg twice daily did not modify the rate or extent of levetiracetam absorption or its plasma clearance or urinary excretion. There also was no effect on exposure to and the excretion of the primary metabolite, ucb L057.

Other Antiepileptic Drugs

Potential drug interactions between immediate-release KEPPRA tablets and other AEDs (carbamazepine, gabapentin, lamotrigine, phenobarbital, phenytoin, primidone and valproate) were also assessed by evaluating the serum concentrations of levetiracetam and these AEDs during placebo-controlled clinical studies. These data indicate that levetiracetam does not influence the plasma concentration of other AEDs and that these AEDs do not influence the pharmacokinetics of levetiracetam.

Oral Contraceptives

Immediate-release KEPPRA tablets (500 mg twice daily) did not influence the pharmacokinetics of an oral contraceptive containing 0.03 mg ethinyl estradiol and 0.15 mg levonorgestrel, or of the luteinizing hormone and progesterone levels, indicating that impairment of contraceptive efficacy is unlikely. Coadministration of this oral contraceptive did not influence the pharmacokinetics of levetiracetam.

Digoxin

Immediate-release KEPPRA tablets (1000 mg twice daily) did not influence the pharmacokinetics and pharmacodynamics (ECG) of digoxin given as a 0.25 mg dose every day. Coadministration of digoxin did not influence the pharmacokinetics of levetiracetam.

Warfarin

Immediate-release KEPPRA tablets (1000 mg twice daily) did not influence the pharmacokinetics of R and S warfarin. Prothrombin time was not affected by levetiracetam. Coadministration of warfarin did not affect the pharmacokinetics of levetiracetam.

Probenecid

Probenecid, a renal tubular secretion blocking agent, administered at a dose of 500 mg four times a day, did not change the pharmacokinetics of levetiracetam 1000 mg twice daily. C^ss max of the metabolite, ucb L057, was approximately doubled in the presence of probenecid while the fraction of drug excreted unchanged in the urine remained the same. Renal clearance of ucb L057 in the presence of probenecid decreased 60%, probably related to competitive inhibition of tubular secretion of ucb L057. The effect of immediate-release KEPPRA tablets on probenecid was not studied.

KEPPRA XR levels may decrease during pregnancy.

Pregnancy Category C

There are no adequate and well-controlled studies in pregnant women. In animal studies, levetiracetam produced evidence of developmental toxicity, including teratogenic effects, at doses similar to or greater than human therapeutic doses. KEPPRA XR should be used during pregnancy only if the potential benefit justifies the potential risk to the fetus.

Oral administration of levetiracetam to female rats throughout pregnancy and lactation led to increased incidences of minor fetal skeletal abnormalities and retarded offspring growth pre-and/or postnatally at doses ≥ 350 mg/kg/day (equivalent to the maximum recommended human dose of 3000 mg [MRHD] on a mg/m² basis) and with increased pup mortality and offspring behavioral alterations at a dose of 1800 mg/kg/day (6 times the MRHD on a mg/m² basis). The developmental no effect dose was 70 mg/kg/day (0.2 times the MRHD on a mg/m² basis). There was no overt maternal toxicity at the doses used in this study.

Oral administration of levetiracetam to pregnant rabbits during the period of organogenesis resulted in increased embryofetal mortality and increased incidences of minor fetal skeletal abnormalities at doses ≥ 600 mg/kg/day (4 times MRHD on a mg/m² basis) and in decreased fetal weights and increased incidences of fetal malformations at a dose of 1800 mg/kg/day (12 times the MRHD on a mg/m² basis). The developmental no effect dose was 200 mg/kg/day (equivalent to the MRHD on a mg/m² basis). Maternal toxicity was also observed at 1800 mg/kg/day.

When levetiracetam was administered orally to pregnant rats during the period of organogenesis, fetal weights were decreased and the incidence of fetal skeletal variations was increased at a dose of 3600 mg/kg/day (12 times the MRHD). 1200 mg/kg/day (4 times the MRHD) was a developmental no effect dose. There was no evidence of maternal toxicity in this study.

Treatment of rats with levetiracetam during the last third of gestation and throughout lactation produced no adverse developmental or maternal effects at oral doses of up to 1800 mg/kg/day (6 times the MRHD on a mg/m² basis).

Pregnancy Registry

To provide information regarding the effects of in utero exposure to KEPPRA XR, physicians are advised to recommend that pregnant patients taking KEPPRA XR enroll in the North American Antiepileptic Drug (NAAED) pregnancy registry. This can be done by calling the toll free number 1-888-233-2334, and must be done by the patients themselves. Information on the registry can also be found at the website http://www.aedpregnancyregistry.org/.

The following adverse reactions are discussed in more details in other sections of labeling:

• Psychiatric Reactions
• Suicidal Behavior And Ideation
• Somnolence And Fatigue
• Serious Dermatological Reactions
• Coordination Difficulties
• Withdrawal Seizures
• Hematologic Abnormalities
• Seizure Control During Pregnancy

Clinical Trials Experience

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

The prescriber should be aware that the adverse reaction incidence figures in the following table, obtained when KEPPRA XR was added to concurrent AED therapy, cannot be used to predict the frequency of adverse reactions in the course of usual medical practice where patient characteristics and other factors may differ from those prevailing during clinical trials. Similarly, the cited frequencies cannot be directly compared with figures obtained from other clinical investigations involving different treatments, uses, or investigators. An inspection of these frequencies, however, does provide the prescriber with one basis to estimate the relative contribution of drug and non-drug factors to the adverse reaction incidences in the population studied.

KEPPRA XR Tablets

In the controlled clinical study using KEPPRA XR in patients with partial onset seizures, the most frequently reported adverse reactions in patients receiving KEPPRA XR in combination with other AEDs, for events with rates greater than placebo, were irritability and somnolence.

Table 3 lists adverse reactions that occurred in at least 5% of epilepsy patients treated with KEPPRA XR participating in the placebo-controlled study and were numerically more common than in patients treated with placebo. In this study, either KEPPRA XR or placebo was added to concurrent AED therapy. Adverse reactions were usually mild to moderate in intensity.

Table 3: Incidence (%) Of Adverse Reactions In The Placebo-Controlled, Add-On Study By Body System (Adverse Reactions Occurred In At Least 5% Of KEPPRA XR-Treated Patients And Occurred More Frequently Than Placebo-Treated Patients)

Discontinuation or Dose Reduction in the KEPPRA XR Controlled Clinical Study

In the controlled clinical study using KEPPRA XR, 5.2% of patients receiving KEPPRA XR and 2.5% receiving placebo discontinued as a result of an adverse reaction. The adverse reactions that resulted in discontinuation and that occurred more frequently in KEPPRA XR-treated patients than in placebo-treated patients were asthenia, epilepsy, mouth ulceration, rash and respiratory failure. Each of these adverse reactions led to discontinuation in a KEPPRA XR-treated patient and no placebo-treated patients.

Table 4 lists the adverse reactions seen in the controlled studies of immediate-release KEPPRA tablets in adult patients experiencing partial onset seizures. Although the pattern of adverse reactions in the KEPPRA XR study seems somewhat different from that seen in partial onset seizure controlled studies for immediate-release KEPPRA tablets, this is possibly due to the much smaller number of patients in this study compared to the immediate-release tablet studies. The adverse reactions for KEPPRA XR are expected to be similar to those seen with immediate-release KEPPRA tablets.

Immediate-Release KEPPRA Tablets

In controlled clinical studies of immediate-release KEPPRA tablets as adjunctive therapy to other AEDs in adults with partial onset seizures, the most frequently reported adverse reactions, for events with rates greater than placebo, were somnolence, asthenia, infection and dizziness.

Table 4 lists adverse reactions that occurred in at least 1% of adult epilepsy patients treated with immediate-release KEPPRA tablets participating in placebo-controlled studies and were numerically more common than in patients treated with placebo. In these studies, either immediate-release KEPPRA tablets or placebo was added to concurrent AED therapy. Adverse reactions were usually mild to moderate in intensity.

Table 4: Incidence (%) Of Adverse Reactions In Placebo-Controlled, Add-On Studies In Adults Experiencing Partial Onset Seizures By Body System (Adverse Reactions Occurred In At Least 1% Of Immediate-Release KEPPRA-Treated Patients And Occurred More Frequently Than Placebo-Treated Patients)

In addition, the following adverse reactions were seen in other well-controlled studies of immediate-release KEPPRA tablets: balance disorder, disturbance in attention, eczema, hyperkinesia, memory impairment, myalgia, personality disorders, pruritus, and vision blurred.

Comparison of Gender, Age and Race

There are insufficient data for KEPPRA XR to support a statement regarding the distribution of adverse experience reports by gender, age and race.

Postmarketing Experience

In addition to the adverse reactions listed above for immediate-release KEPPRA tablets, the following adverse events have been identified during postapproval use of immediate-release KEPPRA tablets. Because these reactions are reported voluntarily from a population of uncertain size, it is not always possible to reliably estimate their frequency or establish a causal relationship to drug exposure. The listing is alphabetized: abnormal liver function test, choreoathetosis, dyskinesia, erythema multiforme, hepatic failure, hepatitis, leukopenia, neutropenia, pancreatitis, pancytopenia (with bone marrow suppression identified in some of these cases), thrombocytopenia, and weight loss. Alopecia has been reported with immediate-release KEPPRA use; recovery was observed in majority of cases where immediate-release KEPPRA was discontinued.

Signs, Symptoms And Laboratory Findings Of Acute Overdosage In Humans

The signs and symptoms for KEPPRA XR overdose are expected to be similar to those seen with immediate-release KEPPRA tablets.

The highest known dose of oral immediate-release KEPPRA received in the clinical development program was 6000 mg/day. Other than drowsiness, there were no adverse reactions in the few known cases of overdose in clinical trials. Cases of somnolence, agitation, aggression, depressed level of consciousness, respiratory depression and coma were observed with immediate-release KEPPRA overdoses in postmarketing use.

Management Of Overdose

There is no specific antidote for overdose with KEPPRA XR. If indicated, elimination of unabsorbed drug should be attempted by emesis or gastric lavage; usual precautions should be observed to maintain airway. General supportive care of the patient is indicated including monitoring of vital signs and observation of the patient's clinical status. A Certified Poison Control Center should be contacted for up to date information on the management of overdose with KEPPRA XR.

Hemodialysis

Standard hemodialysis procedures result in significant clearance of levetiracetam (approximately 50% in 4 hours) and should be considered in cases of overdose. Although hemodialysis has not been performed in the few known cases of overdose, it may be indicated by the patient's clinical state or in patients with significant renal impairment.

Effects On QTc Interval

The effects of KEPPRA XR on QTc prolongation is expected to be the same as that of immediate-release KEPPRA. The effect of immediate-release KEPPRA on QTc prolongation was evaluated in a randomized, double-blind, positive-controlled (moxifloxacin 400 mg) and placebo-controlled crossover study of KEPPRA (1000 mg or 5000 mg) in 52 healthy subjects. The upper bound of the 90% confidence interval for the largest placebo-adjusted, baseline-corrected QTc was below 10 milliseconds. Therefore, there was no evidence of significant QTc prolongation in this study.

Overview

Bioavailability of KEPPRA XR tablets is similar to that of the immediate-release KEPPRA tablets. The pharmacokinetics (AUC and Cmax) were shown to be dose proportional after single dose administration of 1000 mg, 2000 mg, and 3000 mg extended-release levetiracetam. Plasma half-life of extended-release levetiracetam is approximately 7 hours.

Levetiracetam is almost completely absorbed after oral administration. The pharmacokinetics of levetiracetam are linear and time-invariant, with low intra- and inter-subject variability. Levetiracetam is not significantly protein-bound ( < 10% bound) and its volume of distribution is close to the volume of intracellular and extracellular water. Sixty-six percent (66%) of the dose is renally excreted unchanged. The major metabolic pathway of levetiracetam (24% of dose) is an enzymatic hydrolysis of the acetamide group. It is not liver cytochrome P450 dependent. The metabolites have no known pharmacological activity and are renally excreted. Plasma half-life of levetiracetam across studies is approximately 6-8 hours. The half-life is increased in the elderly (primarily due to impaired renal clearance) and in subjects with renal impairment.

Absorption And Distribution

Extended-release levetiracetam peak plasma concentrations occur in about 4 hours. The time to peak plasma concentrations is about 3 hours longer with extended-release levetiracetam than with immediate-release tablets.

Single administration of two 500 mg extended-release levetiracetam tablets once daily produced comparable maximal plasma concentrations and area under the plasma concentration versus time as did the administration of one 500 mg immediate-release tablet twice daily in fasting conditions. After multiple dose extended-release levetiracetam tablets intake, extent of exposure (AUC0-24) was similar to extent of exposure after multiple dose immediate-release tablets intake. Cmax and Cmin were lower by 17% and 26% after multiple dose extended-release levetiracetam tablets intake in comparison to multiple dose immediate-release tablets intake. Intake of a high fat, high calorie breakfast before the administration of extended-release levetiracetam tablets resulted in a higher peak concentration, and longer median time to peak. The median time to peak (Tmax) was 2 hours longer in the fed state.

Two 750 mg extended-release levetiracetam tablets were bioequivalent to a single administration of three 500 mg extended-release levetiracetam tablets.

Metabolism

Levetiracetam is not extensively metabolized in humans. The major metabolic pathway is the enzymatic hydrolysis of the acetamide group, which produces the carboxylic acid metabolite, ucb L057 (24% of dose) and is not dependent on any liver cytochrome P450 isoenzymes. The major metabolite is inactive in animal seizure models. Two minor metabolites were identified as the product of hydroxylation of the 2-oxo-pyrrolidine ring (2% of dose) and opening of the 2-oxo-pyrrolidine ring in position 5 (1% of dose). There is no enantiomeric interconversion of levetiracetam or its major metabolite.

Elimination

Levetiracetam plasma half-life in adults is 7 ± 1 hour and is unaffected by either dose or repeated administration. Levetiracetam is eliminated from the systemic circulation by renal excretion as unchanged drug which represents 66% of administered dose. The total body clearance is 0.96 mL/min/kg and the renal clearance is 0.6 mL/min/kg. The mechanism of excretion is glomerular filtration with subsequent partial tubular reabsorption. The metabolite ucb L057 is excreted by glomerular filtration and active tubular secretion with a renal clearance of 4 mL/min/kg. Levetiracetam elimination is correlated to creatinine clearance. Levetiracetam clearance is reduced in patients with impaired renal function.