Fenazepams

Quick links to important sections

Fenazepams

Treatment option:

Medically reviewed

Marina Burgos

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 Fenazepams

Phenazepam (also known as Fenazepam) is a potent substance that belongs to the benzodiazepine pharmacological class, similar to drugs like diazepam. It is chemically defined by the formula C15H10BrClN2O and acts as a central nervous system depressant.


Quick Facts

Property Description
Active ingredient Phenazepam
Form Tablet (most common)
Pharmacological class Benzodiazepine
Common use (CIS countries) Anxiety, insomnia, withdrawal syndromes
Origin Former Soviet Union (1970s)

Global Status and Potency

Phenazepam was developed in the former Soviet Union during the 1970s and has been an approved prescription medication in Russia and other Commonwealth of Independent States (CIS) countries since 1978. Its primary use in these regions is to manage neurological and mental health conditions.

Phenazepam is characterized by its high potency, a key differentiating factor of its pharmacological profile. The substance possesses strong anxiolytic (anti-anxiety) and sedative-hypnotic (sleep-inducing) properties. In authorized regions, it is used to help patients feel calmer and to assist with sleep difficulties, such as managing acute situational anxiety.

In contrast, Phenazepam is not approved for medical use in the United States and is generally not recognized for accepted medical uses in most of Western Europe. Due to its potent effects, it is recognized as a substance of potential concern and is subject to international control. This status emphasizes its position as a highly effective but tightly controlled substance requiring strict medical supervision.

Regulatory References

  1. CND Decision on Phenazepam Scheduling

What side effects are possible with Fenazepams?

Possible side effects and safety information

The official safety profile for Fenazepams, a potent benzodiazepine, is structured around its effects on the central nervous system (CNS) and recognized risks documented in regulatory sources.


Documented Adverse Reactions

Adverse reactions are primarily associated with Nervous System Disorders and include effects such as drowsiness, dizziness, loss of coordination (ataxia), and amnesia. Other documented effects include hiccups and slurred speech. Formal frequency classifications (e.g., 'common', 'rare') are not consistently published in the publicly available English-language government summaries for this agent; reactions are listed descriptively as being associated with its use.


Serious Safety Concerns and Restrictions

Regulatory documents emphasize serious risks associated with high doses or concomitant use. The most severe documented outcomes include Respiratory Depression, Coma, and Death, especially when the medicine is combined with other Central Nervous System (CNS) depressants, such as alcohol and opioids. This combination is listed as significantly increasing the risk of adverse outcomes.


Time- and Population-Related Safety Patterns

Safety information explicitly links prolonged use to the development of physical dependence and the potential for a severe withdrawal syndrome upon abrupt cessation. Symptoms of withdrawal may include seizures or convulsions. For older adults, safety statements indicate increased sensitivity and altered metabolism of long-acting benzodiazepines, which is a key safety pattern for this drug class. The medicine is officially documented as having a potential for abuse, misuse, and addiction.

Overdose and Emergency Response

Fenazepams overdose is primarily characterized by severe Central Nervous System (CNS) depression. Documented manifestations range from somnolence, confusion, and lethargy to a state of stupor or coma. Neurological signs accompanying overdose commonly include ataxia (impaired coordination) and slurred speech (dysarthria). The official profile also notes that paradoxical reactions, such as agitation, may occur in some cases.

The most serious outcomes officially described are respiratory depression and hypotension, which can escalate to apnea and severe cardiovascular compromise. Regulatory documents emphasize that these life-threatening effects are significantly potentiated when Fenazepams is co-ingested with other CNS depressants, particularly alcohol or opioids. Specific considerations are noted for pediatric patients, who may present with pronounced ataxia, and older adults, who are cited as being at higher risk due to altered drug clearance.

Immediate medical attention must be sought if any signs of profound sedation, difficulty breathing, or loss of consciousness are observed, as this constitutes a medical emergency mandated by regulatory authorities.

Management is primarily symptomatic and supportive, focusing on maintaining an open airway and monitoring vital signs. Although Flumazenil is a documented antidote, its application is carefully constrained in official guidelines. Continuous cardiorespiratory and neurological observation is required until the patient is stable.

Therapeutic Uses of Fenazepams

Phenazepam is relevant in therapeutic contexts where supportive relief across several domains is needed, particularly when symptoms create noticeable functional strain or distress. It is commonly used in conditions characterized by periods of heightened symptoms and is applied in clinical settings that involve acute or unstable symptom patterns.

The substance has been used in clinical practice to treat a range of conditions, including anxiety, epilepsy, alcohol withdrawal syndrome, and sleep disorders. It is applied across domains where additional symptomatic support is needed to address symptom clusters that may become intense or disruptive.

It may assist with symptoms related to emotional tension, symptoms that interfere with daily functioning (such as insomnia), symptoms of increased neurological or muscular activity, and acute phases of alcohol withdrawal. This medication contributes to easing the overall symptom load and supports the patient during difficult episodes by easing distress.


Quick Facts: Symptomatic Relief Domains

Focus Area Benefit Provided
Emotional Tension / Anxiety Helps maintain a sense of stability when symptoms are more noticeable.
Sleep Disturbance / Insomnia Supports general well-being during symptomatic phases.
Motor Overactivity / Spasms Assists with maintaining functional stability.
Acute Withdrawal States Applied in scenarios where additional management of discomfort is required.

Regulatory References

  1. Drug Enforcement Administration (DEA) Diversion Control

Eligibility and Restrictions for Use

Fenazepams eligibility profile is strictly defined by regulatory documentation in the Commonwealth of Independent States (CIS) countries where it is an approved prescription medicine. The official rules establish clear exclusions and conditional use requirements, prohibiting the medicine for groups where the risk is unacceptably high. Use is limited to the adult population for licensed therapeutic purposes.

Eligibility Scope

Category Regulatory Status
Contraindicated Populations Must not be used in patients with severe hepatic impairment, Myasthenia Gravis, severe respiratory depression, acute pulmonary insufficiency, narrow-angle glaucoma, or known hypersensitivity to benzodiazepines.
Age-Group Restrictions Safety and efficacy are not established for the pediatric population (children and adolescents). Older adults require special care due to increased sensitivity to adverse effects.
Vulnerable Physiological States Use is not recommended for women who are pregnant or breastfeeding, as the drug is documented to pass to the fetus or infant.
Condition-Specific Restrictions Caution is required for patients with impaired kidney function, chronic pulmonary insufficiency, and those with a history of alcohol or drug dependence, highlighting the potential for misuse.

These eligibility classifications serve as the official regulatory basis, clearly outlining the mandatory limitations on the medicine's use. The profile dictates who can and cannot use Fenazepams based on absolute prohibitions and restrictions tied to specific physiological and disease states.

What should I know about interactions with other medicines?

Interactions with other medicines and products

Fenazepam's interaction profile is derived from established regulatory warnings for the benzodiazepine pharmacological class, focusing on documented pharmacodynamic and pharmacokinetic constraints. All interaction statements are consistent with official government prescribing information.

Documented Interaction Constraints

The primary constraint is the risk of Pharmacodynamic Synergism. Co-administration with other Central Nervous System (CNS) Depressants, particularly Opioids, carries a documented risk of profound sedation, respiratory depression, coma, and death. This constraint necessitates the strict avoidance of Alcohol due to the synergistic enhancement of depressant effects.

A second critical constraint involves Pharmacokinetic Inhibition. Fenazepam's clearance can be affected by substances that inhibit its metabolism via the Cytochrome P450 3A (CYP3A) enzyme system. Co-administration with strong CYP3A Inhibitors, such as Ketoconazole or Itraconazole, is often classified as a contraindicated combination in official labeling due to the resulting increase in drug plasma concentration and associated adverse risks.

Interaction Type Interacting Substance/Class Official Outcome Description
Pharmacodynamic Opioids, Alcohol, CNS Depressants Additive/synergistic CNS depressant effects
Pharmacokinetic Strong CYP3A Inhibitors Increased plasma concentration; reduced clearance

Population-Specific Notes: Regulatory documentation notes that Geriatric Patients may exhibit increased sensitivity to the effects of the drug and potential for enhanced adverse outcomes from co-administered interacting drugs.

Mechanism of Action

Fenazepam is a central nervous system depressant that acts as an agonist at the gamma-aminobutyric acid A (GABAA) receptor complex. This action potentiates the inhibitory neurotransmission mediated by endogenous GABA. Specifically, Fenazepam binds to an allosteric site on the GABAA receptor, commonly located at the interface of the alpha and gamma subunits. This binding event induces a conformational change in the receptor structure, which increases the frequency of the integral chloride ion channel opening. The resulting influx of Cl^- ions into the postsynaptic neuron causes hyperpolarization. This hyperpolarization decreases the membrane potential, which in turn reduces neuronal excitability and diminishes signal transmission across specific central nervous system pathways.

Dosage and Administration Information

How to Use Fenazepams: Official Administration Guidelines

Administration of Phenazepam is typically structured based on the required speed of action and dosage form. The medicine is most commonly available as 0.5 mg and 1 mg tablets for oral intake. For situations requiring rapid clinical response, injectable solutions (e.g., 0.1% or 0.3% concentrations) are utilized via intramuscular (IM) or intravenous (IV) routes. All forms of administration are performed under close medical supervision.

The standard adult dosing protocol involves dividing the total daily amount. The usual therapeutic oral dose is 0.5 mg administered two to three times per day. The maximum total daily dose for adults is generally noted not to exceed 10 mg.

The usage protocol specifies limits on treatment duration. Therapy is intended for short-term use and should not normally exceed 2 weeks. However, therapy may be prolonged for up to 2 months in select cases that require cautious, specialized consideration. A procedural requirement for ending treatment is that the dose must be gradually reduced (tapering) to conclude the course and prevent withdrawal syndrome.

Population-specific adjustments are established for certain groups. Older adults are typically administered lower doses with caution. Use of the medicine is also generally avoided in cases of severe hepatic impairment. No specific instructions are provided regarding intake with or without food.

Recent Clinical Evidence

Research Evidence / Overview of Studies for Fenazepams


Evidence for use in Anxiety Disorders and Emotional Tension

Research has studied Fenazepams in the context of conditions characterized by fluctuating or episodic manifestations of anxiety and emotional tension. Studies, including short-term randomized controlled trials (RCTs) and comparative trials, examined how symptoms change over defined time intervals. The research focused on outcomes monitoring physiological strain or stress, such as measuring changes in anxiety assessment scores over short time intervals.

However, the existing evidence base has several limitations. A significant portion of the primary data was generated several decades ago, and its study methods may not align with current international research standards. Furthermore, the full body of peer-reviewed clinical data detailing these findings is scarce in internationally indexed scientific literature. This means that while Fenazepams was studied for these conditions, the certainty remains low due to the age and accessibility of the data.


Evidence for use in Sleep Disturbance and Insomnia

Fenazepams was evaluated in clinical observations and studies that were not randomized involving adults who were experiencing sleep disturbance. The researchers explored patient-reported outcomes describing perceived discomfort and outcomes reflecting daily functioning. Research highlights changes measured during the study period relating to factors such as sleep quality and duration.

Evidence is limited in this domain, particularly concerning high-quality, modern RCTs specifically designed to assess chronic insomnia. The primary outcomes used in these studies are often highly reliant on patient self-report. Therefore, the data provides limited insight into long-term outcomes or the stability of measured changes beyond brief administration periods.


Long-Term Follow-up and Durability of Evidence

Research exploring long-term effects are not fully established for Fenazepams. The majority of foundational clinical trials used follow-up durations that were limited, often lasting only a few weeks. This means there is limited information for long-term outcomes related to the stability of measured changes. Existing studies provide limited insight into continuous or maintenance therapy.

Key Studies & References

  1. PHENAZEPAM (Street Names: Bonsai, Soviet Benzo, Fenaz, Panda) - DEA Diversion Control Division
  2. ACMD - Phenazepam advice - GOV.UK (Advisory Council on the Misuse of Drugs)
  3. Species differences in phenazepam kinetics and metabolism - PubMed

Frequently Asked Questions (FAQ)

Common questions about Fenazepams (FAQ)


Q: Is Fenazepams described as a fast-acting or slow-acting medication?

A: Official documents classify Fenazepams as a long-acting substance. This classification is due to its prolonged elimination half-life, which is documented to be up to approximately 60 hours in humans. Its typical onset of effect is also delayed, usually occurring two to four hours after oral administration.


Q: How quickly does a person typically start feeling the effects of Fenazepams?

A: According to official pharmacokinetic data, the concentration of Fenazepams in the blood typically reaches its peak within 2 to 4 hours after oral intake. This timeframe generally indicates when the medicine’s main effects may begin to be noticeable.


Q: How long does the effect of Fenazepams generally last?

A: The duration of the drug's effect is often linked to its elimination half-life. Fenazepams has a prolonged elimination half-life documented to be up to approximately 60 hours, which indicates a sustained presence and potential effect in the body.


Q: What is the half-life of Fenazepams as described in official documents?

A: Pharmacokinetic studies summarized in official documents indicate that the medicine has a long elimination half-life of approximately 60 hours in humans. The half-life refers to the time it takes for half of the drug to be eliminated from the body. This long duration of elimination contributes to the drug's sustained presence in the system.


Q: Do official documents mention tolerance development with Fenazepams?

A: Yes, studies and official safety documents note that Fenazepams may induce tolerance with repeated use. This is a characteristic described for drugs in the benzodiazepine class. Tolerance is when the body may need a higher amount of the medicine to achieve the same initial effect over time.


Q: Can Fenazepams cause changes in mood or behavior?

A: Official safety information includes reports of adverse effects that may impact mood and behavior. These reported changes include symptoms such as depression, anxiety, irritability, and alterations in overall mood. These effects are documented as being associated with its use.


Q: Can Fenazepams affect blood pressure readings?

A: Documented adverse reactions associated with the drug class profile include effects on the circulatory system. Specifically, these reports mention the possibility of hypotension, which is the clinical term for low blood pressure.


Q: Does Fenazepams have a common street name or nickname?

A: Reports from governmental law enforcement and drug control agencies note that the substance has been identified with several unofficial names in non-medical contexts. These names include Soviet Benzo and Panda.


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

A: Fenazepams is the non-proprietary, or generic, name for the active substance. Official regulatory labeling in the regions where it is approved also lists it under various brand names. Examples of these brand names include Elzepam and Phenzitat.


Q: What are the official sources for regulatory information on Fenazepams?

A: Fenazepams is officially approved for medical use primarily in Russia and other Commonwealth of Independent States (CIS) countries. Regulatory information comes from these national authorities, and international bodies like the World Health Organization (WHO) also provide assessment documentation.


Q: What are the signs of a potential allergic reaction to Fenazepams?

A: The product label warns against use in patients with a known hypersensitivity (allergic reaction) to benzodiazepines. Serious hypersensitivity reactions described in drug class warnings can include symptoms like fever, rash, and the involvement of internal organs.


Q: Can Fenazepams interact with herbal supplements?

A: Official documents warn against co-administration with substances that inhibit the CYP3A enzyme system, which is involved in drug processing in the body. Since some herbal supplements may affect this enzyme system, regulatory warnings suggest caution may be warranted.


Q: Can Fenazepams interact with birth control pills?

A: Official prescribing information does not provide a direct statement regarding hormonal contraceptives. However, some anti-seizure medications within the benzodiazepine class are documented to alter the metabolism of hormonal contraceptives.


Q: Does Fenazepams interact with common over-the-counter cold medicines?

A: Regulatory documentation places a constraint on combining Fenazepams with other Central Nervous System (CNS) depressants due to the risk of enhanced sedative effects. Some common over-the-counter cold and flu medicines, such as those containing first-generation antihistamines, fall into this depressant category.


Q: Are there any lifestyle changes that are often mentioned alongside Fenazepams use?

A: Official safety protocols document a constraint requiring the strict avoidance of alcohol and other central nervous system depressants while using this medicine. Safety documentation also highlights the need for caution when operating heavy machinery or driving due to the documented CNS side effects.


Q: Can Fenazepams be crushed or split according to the product labeling?

A: Official product labeling for most oral tablets does not typically include instructions for crushing or splitting. This action may alter the intended absorption rate and is generally outside the scope of regulatory approval unless the tablet has a specific scoring feature.


Q: Does Fenazepams show up on standard drug tests?

A: Fenazepams belongs to the benzodiazepine pharmacological class. It is possible for Fenazepams or its metabolites to be detected in screenings designed to identify substances in this class.

How should Fenazepams be stored and disposed of?

How to Store and Dispose of Fenazepams?

As a potent benzodiazepine, fenazepam's storage and disposal are governed by strict regulatory protocols for controlled substances.

Official Storage Requirements

  • Security and Accessibility: Fenazepam must be stored securely in a locked cabinet and placed out of the sight and reach of children and pets to prevent unauthorized access.
  • Environmental Protection: The medicine should be kept in its tightly closed original container to protect it from moisture and light, and storage must avoid extreme temperatures such as freezing or excessive heat.

Disposal Instructions

  • Preferred Method: Unused or expired fenazepam should primarily be disposed of through an official drug take-back program or mail-back service.
  • Household Disposal: If no take-back option is available, the drug must be removed from its container, mixed with an unappealing material (like coffee grounds or dirt), sealed in a bag, and then placed in the household trash. Personal information must be removed from the label. The product must not be flushed down the toilet.

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

Available in countries:

Equivalent of Fenazepams found in:

A-Z Index: