Clonil

Quick links to important sections

Medically reviewed

Laura Arias

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 Clonil

Property Description
Active ingredient Clonazepam
Form Oral tablets, ODTs, solution
Pharmacological class Benzodiazepine / Anticonvulsant
Common use Stabilizing nerve activity
Origin Synthetic compound

Clonil is the trade name for a prescription-only medicine whose sole active component is Clonazepam. The medicine is a synthetic compound that is internationally classified as belonging to the benzodiazepine class. Clonil is clinically recognized for its long-acting profile compared to some shorter-acting benzodiazepines.

As a high-level classification, Clonil functions as a Central Nervous System (CNS) depressant, which qualifies it therapeutically as both an anticonvulsant (anti-epileptic drug) and an anxiolytic agent. The mechanism of action of Clonazepam involves the positive allosteric modulation of the gamma-Aminobutyric acid (GABA)-A receptor complex. This means the medicine helps to quiet excessive electrical and chemical signaling in the brain by boosting its natural 'brake' system.

Composition, Forms, and General Therapeutic Purpose

Clonil is consistently manufactured as a single-ingredient product, containing only Clonazepam combined with necessary pharmaceutical excipients for stability and optimal oral delivery. The medication is specifically formulated for the oral route of administration, meaning it must be ingested.

The active ingredient is typically available in several dosage forms, including conventional tablets, specialized Orally Disintegrating Tablets (ODT), and an oral solution. This range of forms ensures flexible patient administration. The overarching general therapeutic purpose of Clonil is to promote neurological stability. The primary clinical benefit of this action is the stabilization of neuronal activity, which forms the foundation for its established role in regulating conditions characterized by uncontrolled or overactive brain signaling, such as the maintenance of control over chronic seizure activity.

Regulatory References

  1. World Health Organization (WHO)
  2. U.S. National Library of Medicine

What side effects are possible with Clonil?

Possible Side Effects and Safety Information

Clonazepam's official safety profile, as documented in regulatory materials, is characterized by effects on the central nervous system, reflecting its classification as a benzodiazepine.

Frequency-Classified Adverse Reactions

Adverse reactions are formally categorized by frequency, with many effects often subsiding after the initial treatment period. The most common effects are:

  • Very Common: Drowsiness, sedation, fatigue, and ataxia (impaired coordination).
  • Common: Dizziness, difficulty concentrating, cognitive impairment, depression, muscle weakness, and blurred vision.

Less frequent, but documented, adverse effects include hypersensitivity reactions and certain paradoxical responses, such as excitation or hostility.

Serious Adverse Reactions and Restrictions

Regulatory documentation highlights several clinically significant safety concerns. The risk of respiratory depression is documented, particularly when the medicine is co-administered with other central nervous system depressants, such as opioids. As an antiepileptic drug, a risk of suicidal thoughts or behavior is officially noted. Furthermore, continuous, long-term administration carries the risk of physical dependence and potential for severe withdrawal reactions, including seizures, upon abrupt discontinuation.

Use is restricted (contraindicated) in individuals with specific health conditions, including severe hepatic impairment (liver disease) and severe respiratory insufficiency.

Population-Specific Safety Notes

The safety profile includes specific notes for defined populations. Older adults are officially noted to be at increased risk of sedation, confusion, and resulting falls or fractures. Caution is also noted for those with mild to moderate hepatic impairment.

Overdose and Emergency Response

Clonil (Clonazepam) overdose is officially described as a progression of Central Nervous System (CNS) depression, ranging from mild effects to severe, life-threatening outcomes. The documented manifestations begin with somnolence, profound confusion, lethargy, ataxia (impaired coordination), and slurred speech (dysarthria), potentially advancing to a stuporous state and coma. Physical signs can include hypotonia (reduced muscle tone) and hyporeflexia.

Officially documented severe risks involve the Cardiorespiratory System, specifically respiratory depression, apnea, and hypotension. The risk of death is significantly increased when Clonil is ingested in overdose with other CNS depressants, such as alcohol and opioids—a risk explicitly highlighted in regulatory warnings.

When to Seek Urgent Help: When an overdose is suspected, immediate medical attention is required. Regulatory guidance mandates contacting emergency services for specific symptoms, including unresponsiveness, collapse, or any sign of slow or difficult breathing.

Management is defined as symptomatic and supportive care, focusing on maintaining a clear airway and adequate ventilation. The benzodiazepine antagonist Flumazenil is available; however, its use is restricted by regulatory cautions due to the potential risk of precipitating seizures, especially in patients with chronic use. Official labeling also notes that elderly and pediatric patients may be more susceptible to severe manifestations, such as intense drowsiness and confusion.

Therapeutic Uses of Clonil

Clonil (Clonazepam) is commonly used to address symptoms of increased neurological or muscular activity and symptoms related to systemic imbalance. The medication is generally applied in conditions presenting with acute episodes. The conditions in which this medication is commonly used involve seizure disorders (such as myoclonic, absence, and Lennox-Gastaut syndrome) and the treatment of panic disorder.

Symptom Relief and Stabilization

This medication is applied across domains where additional symptomatic support is needed to address disruptive manifestations. In neurological contexts, it plays a role in managing symptom clusters that may become intense or disruptive, such as generalized fits and involuntary jerking. For anxiety, it may offer symptomatic relief that assists patients in coping more steadily with symptom fluctuations, particularly for pronounced symptoms like palpitations and intense fear.

“This use contributes to easing the overall symptom load and supports patients during episodes of heightened discomfort.”

This medication may assist with maintaining functional stability and supports general well-being during symptomatic phases, providing supportive relief when symptoms interfere with daily functioning.


Quick Fact: Relief for Neurological and Anxiety Symptoms This medication is relevant in clinical settings that involve acute or unstable symptom patterns, helping to manage symptoms that interfere with daily comfort across conditions marked by increased central nervous system activity.

Regulatory References

  1. NIH MedlinePlus overview of Clonazepam uses

Eligibility and Restrictions for Use

The official eligibility profile for Clonil (Clonazepam) is defined by regulatory agencies based on a patient’s health status and demographics. Certain populations are explicitly prohibited from using the medicine, while others require special assessment or close monitoring based on labeled restrictions.

Absolute Contraindications

Clonil is formally contraindicated and must not be used in patients with a known hypersensitivity to any benzodiazepines. Use is also prohibited in those with clinical or biochemical evidence of severe liver disease, as well as in individuals diagnosed with Acute Narrow-Angle Glaucoma. The medicine is further contraindicated in patients with Severe Respiratory Insufficiency or Chronic Obstructive Airways Disease.

Age-Group and Conditional Use

Use is established for adults for Seizure Disorders and Panic Disorder, and for children (typically ge 1 month) for certain Seizure Disorders. However, the safety and efficacy for Panic Disorder are not established in patients under 18 years of age. Older adults must use the medicine with caution, and regulators advise using the lowest possible dose due to increased sensitivity. Use is restricted and requires careful assessment in patients with hepatic impairment, renal impairment, and Chronic Pulmonary Insufficiency. Additionally, the medicine is not recommended during pregnancy or lactation without a specific risk-benefit determination.

What should I know about interactions with other medicines?

Interactions with other medicines and products

The officially documented interaction profile for Clonil (Clonazepam) is primarily defined by its effects on the central nervous system (CNS) and its metabolic pathway involving the cytochrome P-450 enzyme system.

Pharmacodynamic Interactions and Restrictions

Co-administration with Opioid analgesics may result in a severe pharmacodynamic interaction, leading to profound sedation, respiratory depression, coma, and death, a risk stated in regulatory warnings. Similarly, the use of alcohol is restricted or must be avoided because it reinforces the CNS-depressant effects of Clonazepam, an interaction that can lead to severe adverse outcomes. The same potentiation of CNS depression applies to co-administration with other general CNS-depressant medicines, such as certain antidepressants and antipsychotics.

Pharmacokinetic Interactions

Interaction Type Interacting Substance Categories Regulatory Outcome
Decreased Exposure Strong CYP3A4 inducers (e.g., Carbamazepine, Phenytoin) Can reduce the plasma concentration of Clonazepam.
Increased Exposure Strong CYP3A4 inhibitors (e.g., Itraconazole, Clarithromycin) Can increase the plasma concentration of Clonazepam.

Population-Specific Constraints

Clonazepam is formally contraindicated in patients with clinical or biochemical evidence of significant liver disease. This restriction exists because the medicine undergoes essential hepatic metabolism, and impaired liver function is officially documented as having the potential to impair drug elimination, increasing the risk of accumulation. Regulatory documents also note that caution is advised when administering the medicine to elderly or debilitated patients.

Mechanism of Action

How Clonil Works

Serotonin and Norepinephrine Transporter Inhibition

This core mechanism involves blocking the reabsorption of the two key neurotransmitters, serotonin and norepinephrine, back into the presynaptic nerve cell terminals. The drug primarily inhibits the Serotonin Transporter (SERT), while its active metabolite, desmethylclomipramine, acts as a significant inhibitor of the Norepinephrine Transporter (NET). By inhibiting these transporters, the drug increases the concentration of these chemicals in the synaptic cleft, which leads to prolonged availability and altered signaling dynamics in specific neural circuits.

Non-Primary Receptor Interactions

The medication possesses a broader pharmacological profile, acting on several other receptors, including cholinergic, histamine ( H1), and alpha1-adrenergic receptors. While these are secondary to the reuptake inhibition, they contribute to the final physiological consequences by modulating other central and peripheral systems, thus producing wider pharmacological effects. The combined action of the parent drug and its metabolite modifies the concentration ratio of neurotransmitters across multiple pathways.

Dosage and Administration Information

How to Use Clonil: Administration Guidelines

Clonil, containing the active ingredient clonazepam, is administered according to a structured protocol. The primary method of administration for outpatient use is the oral route, utilizing conventional tablets, orally disintegrating tablets (ODT), or an oral solution. In acute, supervised clinical situations, the solution for injection may be administered via the intravenous (IV) or intramuscular (IM) route in some regions.


Dosing and Frequency Patterns

The initiation of Clonil treatment involves a low starting daily dose, which is then followed by a gradual titration phase. For adult seizure disorders, the typical starting dose is 1.5 mg per day, divided into three doses, with the maximum dose not to exceed 20 mg per day. For panic disorder, the starting regimen is 0.25 mg taken twice daily, with the dose not exceeding 4 mg per day.

Titration—the gradual increase in dosage—should occur slowly, typically in increments of 0.5 mg to 1 mg no more often than every three days. The total daily dose is usually taken in divided doses to maintain stable levels, but if unequal division is necessary, the largest dose should be taken at bedtime. The medication can be taken with or without food.


Administration Specifics and Special Populations

For conventional tablets, the dose must be swallowed whole with water. Orally disintegrating tablets (ODT) are placed in the mouth and allowed to dissolve, requiring dry-hand handling. The oral solution must be administered using a precise measuring device and may be mixed with non-alcoholic liquids.

For older adults, clinical practice involves starting with a lower daily dose, generally not to exceed 0.5 mg per day, and monitoring the patient closely. The protocol for ending treatment requires a gradual tapering process, where the dose is slowly reduced over time to mitigate discontinuation effects. If a dose is missed, the standard approach is to take only the next scheduled dose at the regular time, without doubling up.

Recent Clinical Evidence

Research Evidence / Overview of Studies for Clonil

Evidence for Use in Panic Disorder

Clonil was studied for conditions characterized by fluctuating or episodic manifestations such as panic disorder, with research primarily relying on short-term, randomized controlled trials (RCTs). These studies were applied in research contexts involving fluctuating or unstable symptoms, and monitored outcomes describing episodic or acute changes, such as the frequency of full panic attacks. The study populations were mainly adult outpatients.

Studies reported measurements of change in the number of panic attacks over the short observation period, typically limited to between six and nine weeks. These findings describe patterns observed in the studies related to outcomes reflecting daily functioning or activity level. Research describes short-term changes and contributes to the broader evidence landscape.

Evidence for Use in Specific Seizure Disorders

Clonil was studied for conditions associated with acute or disruptive episodes, such as various seizure disorders. The evidence base includes short-term RCTs, where the medicine was evaluated alongside existing anti-seizure regimens, and systematic reviews that synthesize the overall data. This research examined outcomes describing episodic or acute changes by monitoring the frequency of specific seizure types, including myoclonic, akinetic, and absence seizures. Studies observed responses over defined time intervals, with the main populations consisting of children, adolescents, and adults across several epilepsy syndromes.

Data show patterns related to the medicine’s evaluation in specific, refractory conditions like Lennox-Gastaut syndrome. However, scientific literature has described observations in some studies suggesting that a reduction in the initial anti-seizure response, known as tolerance development, may occur after a few months of continuous observation.

Research Gaps and Areas of Uncertainty

The follow-up durations were limited in many of the core randomized controlled trials, meaning long-term outcomes are not well characterized. Furthermore, some studies were conducted with modest sample sizes. For seizure disorders, comparative evidence is lacking regarding the evaluation of Clonil as the sole medication (monotherapy) in newly diagnosed cases, leading to low certainty in this specific area. The phenomenon of tolerance development is a consistent point of discussion, and its long-term clinical implications are still emerging and not fully established.

Key Studies & References MedlinePlus Drug Information: Clonazepam

Frequently Asked Questions (FAQ)

Common questions about Clonil (FAQ)

Q: Does Clonil carry a Boxed Warning from regulatory agencies?

Yes. The FDA prescribing information includes a Boxed Warning. This warning highlights the serious risks associated with taking Clonil (clonazepam) concurrently with opioid medications, and also cautions about the risks of abuse, misuse, addiction, physical dependence, and potentially severe withdrawal reactions.

Q: What are the signs of a serious or severe reaction to Clonil?

Regulatory documents describe symptoms that warrant immediate medical attention, such as signs of a severe allergic reaction (hives, swelling of the face, tongue, or throat, or difficulty breathing). Signs of severe central nervous system depression, like extreme sleepiness, slowed breathing, or unresponsiveness, are also described as requiring prompt medical attention.

Q: Is Clonil a controlled substance?

Yes. Clonil (clonazepam) is categorized as a Schedule IV controlled substance by U.S. regulatory bodies. This classification acknowledges the medicine’s potential for misuse, abuse, and dependence.

Q: How quickly do the main effects of Clonil typically begin?

Regulatory pharmacokinetic data indicates that Clonil is quickly absorbed after it is taken by mouth. Maximum concentrations of the medicine in the bloodstream are generally reached within a window of 1 to 4 hours.

Q: What is the relationship between Clonil and serotonin levels?

The primary mechanism of action of Clonil (clonazepam) is to enhance the effects of the inhibitory neurotransmitter, GABA, by modulating the GABA-A receptor complex in the brain. However, scientific literature also notes that Clonazepam has some secondary serotonergic activity, specifically being associated with increased serotonin synthesis.

Q: Does Clonil affect driving or using machinery?

Official warnings state that Clonil can impair a patient’s judgment, thinking, and motor skills. For this reason, official labeling advises patients to avoid driving or operating hazardous machinery until the effects on coordination and mental clarity are known.

Q: Is it possible for Clonil to make anxiety worse at the beginning of treatment?

Yes. Regulatory documents report that when beginning treatment or adjusting dosage, patients may experience new or worsening anxiety, restlessness, agitation, or other unusual changes in mood. These types of paradoxical reactions have been noted.

Q: Do side effects like dry mouth or drowsiness usually lessen over time?

Official product information suggests that common side effects, such as drowsiness and sedation, may be temporary and often resolve or lessen within the first couple of weeks as the body adjusts to the medication. Dry mouth is also a reported side effect.

Q: What is the maximum duration Clonil is typically used for?

Clonil is considered effective for the short-term treatment of conditions like panic disorder. For ongoing, long-term use, the product protocol requires the continuation of therapy to be periodically re-evaluated by a healthcare provider to mitigate the risk of developing dependence.

Q: How does Clonil differ from other similar medications in its class?

Clonil (clonazepam) is structurally classified as a high-potency benzodiazepine with a long-acting profile. Scientific data shows that it has a relatively long elimination half-life when compared to some shorter-acting medicines within the same class.

Q: Can Clonil be taken with other types of antidepressants?

Clonil is classified as a Central Nervous System (CNS) depressant. The official information states that combining it with other CNS depressants, which may include certain antidepressants, can increase the risk of side effects. These potential effects include excessive sleepiness, dizziness, and dangerously slowed breathing.

Q: Does Clonil interact with common allergy medications?

Clonil is a Central Nervous System (CNS) depressant. When taken with other medicines that cause sedation, which can include certain common allergy medications (antihistamines), the risk of excessive drowsiness, dizziness, and extreme sedation is increased.

Q: Are there specific lifestyle changes recommended while taking Clonil?

The official label includes warnings restricting the consumption of alcohol and certain other drugs while using the medication. Furthermore, the label cautions against operating hazardous machinery or driving until the medicine’s effects on motor skills are fully known.

Q: Is weight gain a known side effect of Clonil?

Official reports of side effects have noted both weight gain and weight loss in people taking Clonil for seizure disorders. However, weight changes were not commonly reported by individuals in studies for panic disorder.

Q: Can Clonil cause sexual side effects?

Yes, changes to sexual function have been reported in association with this medicine. These reported side effects include changes in libido (sex drive) and, for men, erectile dysfunction.

Q: Are there special warnings for people with pre-existing heart conditions?

Regulatory labeling indicates that Clonil can potentially cause low blood pressure (hypotension) and heart palpitations. The product label contains a caution for use in elderly patients who may have existing cardiovascular conditions.

Q: Can Clonil affect blood pressure?

Yes, regulatory documents list changes in blood pressure as a reported side effect. Specifically, the medicine can cause low blood pressure, known as hypotension.

Q: Is it normal to experience increased sweating while on Clonil?

Yes. Increased sweating, medically known as diaphoresis, is listed in the official prescribing information as a reported side effect of Clonil. This is a recognized autonomic nervous system effect.

Q: Does Clonil pose a risk for individuals with a history of seizures?

Although Clonil is primarily used as an anti-epileptic drug for seizure control, regulatory documents mention a caution. In rare instances, patients taking the medicine may experience seizures that are different from the types being treated.

Q: How does Clonil affect sleep quality?

As a medicine that causes central nervous system depression, Clonil frequently leads to common effects like drowsiness and sedation. Less frequent, but reported, side effects include difficulty falling or staying asleep (insomnia) and disturbed sleep patterns, such as vivid or unusual dreams.

Q: What is the difference between a tablet and a capsule form of Clonil?

Regulatory labeling describes the available dosage forms as conventional tablets, orally disintegrating tablets (ODTs), and an oral solution. A capsule form of Clonil is not typically listed in the official product information.

Q: Can people with bipolar disorder use Clonil?

Clonil's official regulatory approvals are for the treatment of seizure disorders and panic disorder. However, scientific literature mentions that the medicine has been used in clinical practice off-label to help manage symptoms like acute manic episodes associated with bipolar disorder.

Q: What are the ingredients in Clonil tablets besides the active substance?

Official product descriptions indicate that Clonil tablets contain the active ingredient clonazepam. They also contain inactive excipients, such as lactose, magnesium stearate, microcrystalline cellulose, and corn starch, which are necessary for the tablet structure.

How should Clonil be stored and disposed of?

How to Store and Dispose of Clonil (Clomipramine)

Clonil must be stored at room temperature and kept in the container it came in, with the lid tightly closed. It is essential to protect the medication from excess heat and moisture; therefore, it should not be stored in a bathroom. To prevent accidental ingestion, always keep the medication out of the sight and reach of children and secure all safety caps.

Regarding disposal, the most effective method is to utilize a drug take-back program or mail-back envelope when available. If these options are not accessible, do not flush the medicine down the toilet. Instead, mix the medication with an undesirable substance, such as used coffee grounds or cat litter, place the mixture in a sealed container, and then discard it in the household trash. Always scratch out personal information from the packaging before disposal.

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

Available in countries:

Equivalent of Clonil found in:

A-Z Index: