Clonazepam: uses, side effects and safety
Clonazepam (Klonopin) is a benzodiazepine. It is a US Schedule IV controlled substance. It is prescription only (rx) and remains on the US market.
What is Clonazepam?
Clonazepam is the generic name for Klonopin, and belongs to the Benzodiazepine class.
| Generic name | clonazepam |
|---|---|
| Brand name(s) | Klonopin |
| Drug class | Benzodiazepine |
| US legal status | US Schedule IV · Prescription only (Rx) |
| Route | Oral |
| Prescription required | Yes |
| Elimination half-life | Typically 30 to 40 hours |
| Time to peak concentration | 1-4 (maximum plasma concentrations reached within 1 to 4 hours after oral administration) |
| Metabolism | Biotransformation occurs mainly by reduction of the 7-nitro group to the 4-amino derivative, which can be acetylated, hydroxylated and glucuronidated; cytochrome P-450 including CYP3A may play an important role in clonazepam reduction and oxidation |
What is Clonazepam used for?
Clonazepam is approved by the FDA for the following uses. Approval is granted per indication, and a specific product may not be approved for all of them.
- Seizure disorders: Lennox-Gastaut syndrome (petit mal variant), akinetic seizures, myoclonic seizures, and as adjunct in absence seizures (petit mal) that failed to respond to succinimides
- Panic disorder, with or without agoraphobia
How does Clonazepam work?
The precise mechanism by which clonazepam exerts its antiseizure and antipanic effects is unknown, although it is believed to be related to its ability to enhance the activity of gamma aminobutyric acid (GABA), the major inhibitory neurotransmitter in the central nervous system.
It is metabolised primarily by Biotransformation occurs mainly by reduction of the 7-nitro group to the 4-amino derivative, which can be acetylated, hydroxylated and glucuronidated; cytochrome P-450 including CYP3A may play an important role in clonazepam reduction and oxidation.
The elimination half-life is roughly Typically 30 to 40 hours. Longer half-lives mean the drug and its active metabolites persist in the body for longer after the last dose.
Common side effects of Clonazepam
These are the side effects people report most often. Many diminish after the body adjusts, usually within one to two weeks.
- Seizure trials: drowsiness in approximately 50% of patients, ataxia in approximately 30%, behavior problems in approximately 25%
- Panic disorder trials (n=574): somnolence 37%, depression 7%, coordination abnormal 6%, ataxia 5%
- Confusion
- Depression
- Amnesia
- Increased libido
- Insomnia
- Vertigo
- Paresthesia
What does Clonazepam interact with?
Interactions matter because two safe medicines can become dangerous together. The entries below are the ones most likely to cause harm.
- Opioids (boxed warning: profound sedation, respiratory depression, coma, death)
- Alcohol, narcotics, barbiturates, other hypnotics, antipsychotics, MAO inhibitors, tricyclic antidepressants, and other anticonvulsants potentiate the CNS-depressant action
- CYP3A inducers such as phenytoin, carbamazepine, lamotrigine, and phenobarbital induce clonazepam metabolism, causing an approximately 38% decrease in plasma clonazepam levels
- CYP3A inhibitors (e.g., fluconazole) should be used cautiously because they may impair metabolism and cause exaggerated concentrations and effects
- Phenytoin: clonazepam may influence phenytoin concentrations; monitoring recommended
Use our drug interaction checker before combining any two prescriptions.
Serious side effects and warning signs
Seek emergency care for any of these
- Boxed warning: concomitant use of benzodiazepines and opioids may result in profound sedation, respiratory depression, coma, and death
- Acute withdrawal reactions that can be life-threatening, including seizures
- Protracted withdrawal syndrome lasting weeks to more than 12 months
- Paradoxical reactions such as agitation, irritability, aggression, anxiety, anger, nightmares, hallucinations, and psychoses (more likely in children and the elderly)
- Suicidal behavior and ideation with antiepileptic drugs
- Respiratory depression in patients with compromised respiratory function
- Neonatal sedation and withdrawal syndrome with use late in pregnancy
Suspected overdose or a bad reaction should be reported to Poison Control on 1-800-222-1222. That is staffed around the clock and is free.
Legal status of Clonazepam
Clonazepam is a Schedule IV controlled substance in the United States. That placement is set out in Title 21 of the Code of Federal Regulations, Part 1308, and enforced by the Drug Enforcement Administration. It carries restrictions on prescribing, storage, record-keeping and transfer.
Statutory reference: https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=4acbb7a9-4db5-4497-b8db-9f358b3f6fb4.
Can you get Clonazepam without a prescription?
Short answer: no. Clonazepam is a prescription medication. Sites advertising it without one are either operating illegally or selling something other than what they claim. We explain the legal routes, the counterfeit problem and how to check a source in detail.
Read the full answer: Clonazepam without a prescription →
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What is Clonazepam used for?
Seizure disorders: Lennox-Gastaut syndrome (petit mal variant), akinetic seizures, myoclonic seizures, and as adjunct in absence seizures (petit mal) that failed to respond to succinimides Panic disorder, with or without agoraphobia
What schedule is Clonazepam in the United States?
Clonazepam is a Schedule IV controlled substance in the US, listed at 21 CFR Part 1308. Schedule IV means the drug has a defined potential for abuse and is subject to federal record-keeping, storage and prescribing restrictions.
What are the common side effects of Clonazepam?
The most frequently reported side effects are seizure trials: drowsiness in approximately 50% of patients, ataxia in approximately 30%, behavior problems in approximately 25%, panic disorder trials (n=574): somnolence 37%, depression 7%, coordination abnormal 6%, ataxia 5%, confusion, depression, amnesia, increased libido. Many lessen over the first week or two of treatment.
What should not be combined with Clonazepam?
The most clinically important interactions are with opioids (boxed warning: profound sedation, respiratory depression, coma, death), alcohol, narcotics, barbiturates, other hypnotics, antipsychotics, mao inhibitors, tricyclic antidepressants, and other anticonvulsants potentiate the cns-depressant action, cyp3a inducers such as phenytoin, carbamazepine, lamotrigine, and phenobarbital induce clonazepam metabolism, causing an approximately 38% decrease in plasma clonazepam levels, cyp3a inhibitors (e.g., fluconazole) should be used cautiously because they may impair metabolism and cause exaggerated concentrations and effects. Always give a pharmacist or prescriber a complete list of everything you take, including over-the-counter drugs and supplements.
Sources & references
Important
This site provides educational information only and does not sell, prescribe or dispense medications. Always consult a licensed healthcare provider. This page is not medical advice.