STS

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STS

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Medically reviewed

Rosario Oropesa

Last updated on 22/12/2025

This page provides general, reference-level information compiled from official medical sources. It is not a substitute for professional medical advice, diagnosis, or treatment. For decisions about your health, please consult a qualified healthcare professional.

Overview of STS

Quick Facts

Property Description
Active ingredient Acetaminophen, Alprazolam
Form Solid oral preparations (Tablets)
Pharmacological class Combination Analgesic-Anxiolytic, Benzodiazepine
General purpose Dual relief for pain and anxiety/tension
Origin Synthetic chemical substance

What Type of Medicine is STS?

STS is defined as a synthetic, fixed-dose combination product intended for oral administration, typically as a tablet. Its classification is highly specific, falling into the Combination Analgesic-Anxiolytic pharmacological class. This preparation unifies two distinct active ingredients, Acetaminophen and Alprazolam, into a single unit. The presence of Alprazolam, a Triazolobenzodiazepine, means the product inherently delivers the properties of the Benzodiazepine class alongside the action of a Miscellaneous Analgesic.

What is the General Purpose of the STS Combination?

The general purpose of the STS combination is to provide dual-action relief by addressing both physical discomfort and the associated emotional tension or anxiety. The differentiating factor of STS is the simultaneous delivery of both agents, characterizing its action profile. Acetaminophen works as an analgesic and antipyretic agent, effectively mitigating pain signals and fever. The inclusion of this ingredient helps to ease physical pain.

The addition of Alprazolam provides a calming/sedative effect, reducing heightened emotional tension or anxiety often linked to physical distress. This targeted approach is typically utilized when a patient experiences acute, mild-to-moderate physical discomfort that is significantly compounded by situational anxiety or tension.

What side effects are possible with STS?

Possible side effects and safety information

The official safety profile for the STS combination is derived from the established risks of its two components: the Central Nervous System (CNS) effects of Alprazolam and the potential for hepatic injury from Acetaminophen. Regulatory documents classify adverse reactions based on frequency and system-organ class.

Frequency-Classified Adverse Reactions

Adverse reactions are formally categorized based on the frequency observed in clinical use, primarily from the Alprazolam component's data.

Classification Example Reported Adverse Reactions
Very Common (ge10%) Sedation, Drowsiness, Fatigue, Tiredness
Common (1%–10%) Confusion, Depression, Ataxia (unsteadiness), Slurred speech, Dizziness, Constipation, Dry mouth

System-Organ-Class Safety Groupings

Side effects are documented across several physiological systems. Common targets include Nervous System Disorders (e.g., drowsiness, dizziness) and Gastrointestinal Disorders (e.g., dry mouth, constipation). Official safety information also documents effects on Psychiatric Disorders and the Hepatobiliary Disorders system due to the risk of liver damage from Acetaminophen.

Serious Adverse Reactions and Safety Constraints

The regulatory labeling contains specific, serious warnings. The Alprazolam component carries a warning regarding the risk of profound sedation, respiratory depression, coma, and death when used concomitantly with opioids. High doses of the Acetaminophen component are associated with the risk of acute liver failure. Due to these risks, the medicine is contraindicated in patients with severe hepatic impairment or acute narrow-angle glaucoma.

Population-Specific Safety Notes

Official documents indicate that Geriatric Patients are more susceptible to unwanted effects like severe drowsiness and ataxia, and a lower starting dose is typically necessary. Furthermore, due to the risk of physical dependence, the official profile notes that withdrawal symptoms and seizures can occur upon abrupt cessation.

Overdose and Emergency Response

Overdose and When to Seek Help

The official regulatory documents define the STS overdose profile based on the combined toxicity of Acetaminophen and Alprazolam. Manifestations may initially present as non-specific symptoms like nausea, vomiting, and malaise. These are often accompanied by central nervous system (CNS) effects, including somnolence, confusion, and impaired coordination.

Serious and Life-Threatening Outcomes The severe risks are dual: the Alprazolam component can lead to profound CNS depression, resulting in respiratory depression, severe hypotension, and potentially cardiovascular collapse. The Acetaminophen component carries the critical, delayed risk of fatal hepatic necrosis and acute liver failure. Individuals with pre-existing hepatic impairment or chronic alcohol use are at a documented heightened risk of severe hepatic injury.

Mandated Emergency Action and Management Regulatory guidance mandates that individuals seek immediate medical attention or contact emergency services immediately following any suspected overdose. This action is required even in the absence of initial symptoms, due to the delayed onset of liver toxicity. Official management protocols focus on symptomatic and supportive treatment, with the availability of N-acetylcysteine for acetaminophen toxicity and Flumazenil documented for reversing CNS effects. Continuous monitoring of vital signs and laboratory parameters is necessary for overdose management.

Therapeutic Uses of STS

What STS Treats: Main Uses and Benefits

STS is a medication combining two agents that is commonly used to provide dual-action relief for symptoms related to physical discomfort and associated emotional tension or anxiety, a therapeutic approach relevant in situations where one component of symptoms is exacerbated by the other. The first active component is indicated for the management of anxiety and panic symptoms. The other component, acetaminophen, is generally used to help with symptoms related to physical discomfort, aches, and elevated body temperature.

Relief from Physical Discomfort Compounded by Anxiety

This combination is generally used for managing symptoms related to physical discomfort when they are concurrently accompanied by situational anxiety or heightened emotional tension. It is applied across domains where additional symptomatic support is needed for symptom clusters that may become intense or disruptive. This approach provides support that helps ease the overall symptom burden and contributes to improved day-to-day comfort during symptomatic periods.

Symptomatic Support for Acute Aches and Fever

STS supports the management of symptoms related to systemic imbalance, including general physical aches and fever, which are conditions presenting with systemic or localized discomfort. It is commonly used when short-term symptomatic assistance is needed during phases where the patient experiences increased discomfort. The analgesic component is relevant for easing the symptoms related to physical discomfort.


Quick Fact: Relief for Concurrent Symptoms

Symptom Focus Therapeutic Goal
Physical Pain/Fever Contributes to easing the overall symptom load of acute aches.
Emotional Tension Supports general well-being by managing heightened situational anxiety.

Regulatory References

  1. NIH MedlinePlus overview on Alprazolam

Eligibility and Restrictions for Use

Population Eligibility and Contraindications

Regulatory documents define eligibility for STS (Acetaminophen and Alprazolam combination) by incorporating all restrictions from its active components. Use is strictly contraindicated in several specific populations.

Contraindicated Populations:

  • Patients with known hypersensitivity to alprazolam, other benzodiazepines, or acetaminophen.
  • Individuals with severe hepatic impairment or severe active liver disease.
  • Patients with acute narrow-angle glaucoma.
  • Concomitant use is prohibited with certain strong CYP3A inhibitors (e.g., ketoconazole, itraconazole).

Restricted and Not Recommended Use:

Safety and effectiveness are not established in pediatric patients (under 18), and use is not recommended in this age group. Use is also not recommended during pregnancy or lactation due to the potential for neonatal effects. Older adults (geriatric patients) must use the medicine with caution. Conditional use status applies to patients with impaired respiratory function or certain psychiatric disorders.

What should I know about interactions with other medicines?

The interaction profile of STS (Acetaminophen/Alprazolam) is governed by two distinct active ingredients, establishing multiple mandated co-administration restrictions documented in regulatory labeling.

Contraindicated Combinations and Restrictions

Due to potent inhibition of the CYP3A metabolic pathway, co-administration of STS is contraindicated with certain strong inhibitors, including Ketoconazole and Itraconazole, as this significantly increases Alprazolam plasma concentration and exposure. Furthermore, official labeling requires the product not be co-administered with any other prescription or non-prescription medicine containing Acetaminophen.

Metabolic and Pharmacodynamic Interactions

Pharmacokinetic interactions are frequently documented with medicines that modulate the CYP3A enzyme. CYP3A Inhibitors such as Nefazodone, Fluvoxamine, and Erythromycin may lead to an increase in Alprazolam exposure. Conversely, CYP3A Inducers, including Carbamazepine, accelerate metabolism and decrease plasma concentrations. A significant risk of profound sedation and respiratory depression exists when the Alprazolam component is co-administered with Opioids or other CNS Depressants, resulting in an official boxed warning.

Substance and Population Considerations

The Acetaminophen component carries a specific restriction: chronic, excessive consumption of Alcohol is documented to increase the risk of severe hepatotoxicity. Interaction considerations are also noted for specific populations, including the Elderly, who may exhibit increased susceptibility to CNS-depressant effects, and patients with Severe Hepatic Impairment, where Acetaminophen risk is heightened.

Mechanism of Action

Targeting the Steroid Sulfatase Enzyme

This drug's action begins by physically binding to and inhibiting the Steroid Sulfatase (STS) enzyme, a primary target in the peripheral hormone pathway. This molecular interaction suppresses the enzyme's ability to activate circulating, inactive sulfated steroid reserves (precursors), thereby engaging a mechanism that modulates the conversion rate of steroid precursors. The inhibition of STS is a key step in regulating the peripheral supply of specific steroid hormones.

Modulating Peripheral Hormone Availability

The inhibition of STS initiates a cascade that leads to a pronounced reduction in the amount of active, unconjugated steroid hormones (like Estrone and Estradiol) available in the body's tissues and bloodstream. This targeted pathway adjustment establishes a change in the dynamics of processes driven by these distinct signaling patterns, resulting in a reduction in hormone-dependent cellular activity.

Systemic Reduction in Receptor Signaling

The resulting physiological effect is a systemic and sustained decrease in the stimulation of nuclear receptors that mediate hormone action. By modifying these early molecular steps, the drug modifies the effects originating from high levels of hormone signaling, which establishes a state of reduced activity within targeted pathways and shapes the drug’s resulting biological activity.

Dosage and Administration Information

This information outlines the standard administration instructions for the oral tablet formulation to support the correct use of the medication.

Administration Requirements

The medicine is an oral tablet that must be swallowed whole. It is critical that the tablet is not broken, crushed, or chewed before swallowing to maintain its intended release mechanism.

Requirement Instruction
Route of Administration Oral (by mouth)
Frequency Pattern Once per day (Daily)
Timing in Relation to Meals Take on an empty stomach. This means at least 1 hour before a meal or 2 hours after a meal.
Antacids and Other Medicines Antacids should be taken several hours before or after this medicine to avoid interference.

Dosing and Procedural Rules

Dosage Parameters: The dosage for adults and older pediatric patients is generally prescribed as 800 mg once per day, though a physician may adjust this amount. The correct dose for younger children must be determined by a doctor.

Missed-Dose Instructions: If a dose is missed, take it as soon as you remember. However, if it is almost time for the next scheduled dose (less than 12 hours before), the missed dose should be skipped entirely. Do not take two doses at the same time to make up for a missed dose.

This structured approach to administration—specifying the dose, the daily rhythm, and the required fasting state—summarizes the requirements for the medicine's use.

Recent Clinical Evidence

Research evidence / Overview of Studies for STS

Evidence for use in Major Depressive Disorder (MDD)

The evidence base for Major Depressive Disorder primarily consists of studies like short-term randomized controlled trials and meta-analyses. This research was evaluated in adult populations whose conditions are characterized by fluctuating or episodic manifestations. Researchers examined outcomes related to systemic or functional imbalance by monitoring changes measured during the study period on standardized rating scales for depression.

Findings describe patterns observed in the studies where measurements changed in the observed populations during this defined time interval. Research provides insight into short-term changes in these measured scales. However, a significant gap in this research is that long-term effects are not fully established, and follow-up durations were limited.


Evidence for use in Generalized Anxiety Disorder (GAD)

For Generalized Anxiety Disorder, evidence primarily comes from short-term randomized controlled trials. These trials examined how symptoms change over time in adults whose conditions involve periods of heightened symptoms. Outcomes reflecting daily functioning or activity level was monitored alongside changes in standardized anxiety rating scales. Evidence is limited for outcomes beyond the short-term study periods, and subgroup findings are uncertain for populations such as the elderly or those with certain co-existing medical conditions.


Evidence for use in Obsessive-Compulsive Disorder (OCD)

Research for Obsessive-Compulsive Disorder was evaluated in randomized controlled trials, including both adult and pediatric populations. These studies research explored changes in the severity of symptoms, measured using the Y-BOCS scale, over defined time intervals. Findings describe patterns observed in the studies concerning measurements of symptom severity. A main limitation is that follow-up durations were limited given that OCD is a long-term condition. Sample sizes were modest in some instances, and long-term effects are not fully established for either the adult or pediatric groups.


What is still uncertain about STS

The current evidence contributes to the broader evidence landscape but has several important limitations. Long-term effects are not fully established, and follow-up durations were limited across many trials. Evidence quality varies across studies, and the interpretation of findings is sometimes complicated because findings were mixed or sample sizes were modest. Furthermore, the evidence does not determine whether an individual in a special population will experience similar outcomes.

Key Studies & References

  1. Sheehan Suicidality Tracking Scale (Sheehan-STS): Preliminary Results from a Multicenter Clinical Trial in Generalized Anxiety Disorder
  2. Psychotherapies for Generalized Anxiety Disorder in Adults: A Systematic Review and Network Meta-Analysis of Randomized Clinical Trials

Frequently Asked Questions (FAQ)

Common questions about STS (FAQ)

Q: How does STS work to provide dual relief for pain and anxiety?

A: STS is a fixed-dose combination medicine that works in two ways, based on its active ingredients. The medicine contains Acetaminophen, which functions as an analgesic to help relieve pain. It also includes Alprazolam, a benzodiazepine that acts on the central nervous system to reduce associated emotional tension and anxiety.

Q: How long does the sedation or drowsiness from STS typically last?

A: Sedation and drowsiness are commonly reported side effects. While regulatory information does not specify the exact duration of the side effect itself, it does provide context on how long the medicine stays in the body. The Alprazolam component has an average elimination half-life of approximately 11.2 hours in healthy adults.

Q: Can STS interact with antibiotics like Erythromycin?

A: Yes, official drug information indicates that certain antibiotics, such as Erythromycin, may interact with STS. Erythromycin is known as a moderate CYP3A inhibitor, which means it can slow down the body's process of breaking down the Alprazolam component. This interaction can lead to a higher concentration of Alprazolam in the body. This interaction is a consideration for dosage adjustments.

Q: Can I stop taking STS abruptly?

A: Official warnings state that abrupt discontinuation of STS should be avoided. Because the medicine contains Alprazolam, stopping suddenly carries a risk of severe withdrawal symptoms and seizures. Official information strongly advises that any change to the regimen, including stopping the medicine, be done through a gradual dose reduction under professional supervision.

Q: What happens if I take STS with other strong CYP3A inhibitors like Ketoconazole?

A: Official labeling states that co-administration (taking the medicines together) is strictly contraindicated (prohibited) with strong CYP3A inhibitors, such as Ketoconazole. These inhibitors significantly impair the body's ability to metabolize (break down) the Alprazolam component. This can lead to dangerously high levels of Alprazolam in the bloodstream and increase the risk of serious adverse reactions.

Q: What evidence is there regarding the long-term effectiveness of STS?

A: Studies and official information indicate that the efficacy (effectiveness) for long-term use, generally defined as use beyond 8–10 weeks, has not been established by the controlled clinical trials. For this reason, official guidelines state that the usefulness of the medicine should be periodically evaluated.

Q: What is the typical time frame for stopping STS after a course of treatment?

A: Regulatory documents note that when reducing the dosage, it should be done in small, gradual steps, such as decreasing by a specific amount over several days. The exact schedule for gradually discontinuing the medicine is determined by a healthcare provider.

Q: What is the physical appearance of the STS tablet (color, shape, markings)?

A: The STS tablets are supplied in various strengths, each of which has a specific and unique appearance. Official drug packaging descriptions provide these details, noting that tablets may be different shapes (e.g., oval, round) and feature different colors and distinct imprint codes for identification.

Q: Can STS be taken with or without food?

A: The STS immediate-release tablet should be taken on an empty stomach. Regulatory instructions specify that this means taking the medicine at least 1 hour before a meal or 2 hours after a meal. This timing is specified in regulatory documents to ensure proper administration.

Q: How should I dispose of unused or expired STS tablets?

A: Due to the presence of a controlled substance, disposal must follow official guidelines. It is recommended to use an authorized drug take-back program when available. If a take-back program is not accessible, the drug should be mixed with an unpalatable substance (like dirt or used coffee grounds) and placed in a sealed bag or container before being discarded with household trash.

Q: Is STS a generic or brand-name drug?

A: STS is technically described as a fixed-dose combination product containing the two active ingredients, Acetaminophen and Alprazolam. While these components are synthetic substances, the product itself may be available under various brand names, or as a generic version.

Q: How soon before or after a meal should I take STS?

A: To maintain an empty stomach for proper administration, the medicine should be taken at least 1 hour before a meal or no sooner than 2 hours after a meal. This timing is specified in regulatory documents to ensure proper administration.

Q: Can I use STS if I have narrow-angle glaucoma?

A: Official regulatory documents list acute narrow-angle glaucoma as a contraindication, meaning the medicine is prohibited for use in patients with this specific, severe form of the condition. A medical professional will determine if a patient’s history of glaucoma is a contraindication.

Q: Why is a lower starting dose recommended for older patients?

A: A lower starting dose is often recommended for older adults (geriatric patients) because official warnings indicate this population may be more susceptible or sensitive to the adverse effects of the Alprazolam component. These unwanted effects include pronounced drowsiness and ataxia, which is a difficulty with balance or coordination.

Q: Is STS effective for all types of anxiety, or specifically Generalized Anxiety Disorder?

A: The Alprazolam component of STS is officially indicated (approved for use) in the management of two specific conditions: Generalized Anxiety Disorder (GAD) and Panic Disorder. This is the official basis for the anxiety-relieving purpose of the combination medicine.

Q: How long after starting STS will I feel the maximum effect?

A: According to the official pharmacology information, the Alprazolam component is designed to be absorbed relatively quickly. It typically reaches its highest concentration in the bloodstream (peak concentration) in approximately 1 to 2 hours after the tablet is swallowed.

Q: What is the risk of liver damage from Acetaminophen in STS?

A: The Acetaminophen component of STS carries an important warning about the risk of acute liver failure, which can sometimes be fatal. This risk is notably increased if the maximum recommended daily dose is exceeded, or if a person consumes chronic, excessive amounts of alcohol while taking the medicine.

How should STS be stored and disposed of?

How to Store and Dispose of STS?

Official regulatory guidelines for STS tablets, a fixed-dose combination product, focus on maintaining stability and security, especially due to its Controlled Substance component (Alprazolam).


Storage Requirements

STS must be stored at Controlled Room Temperature (20 C to 25 C) and protected from excessive heat and moisture. To maintain stability, the tablets must remain in the original, tightly closed container; do not freeze the product.

Child Safety and Disposal

It is mandatory to keep this medicine out of the sight and reach of children and store it securely (locked up) to prevent accidental ingestion and diversion. Disposal of unused or expired tablets must follow official instructions: use an authorized drug take-back program or mix the product with an unpalatable substance and seal it before discarding, as the drug must not be flushed down the toilet.

Attention! Always consult to a doctor or pharmacist before using pills or medicines.

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