Pharmacology · Benzodiazepines
Clonazepam !
A long-acting benzodiazepine used for some seizure types and for panic disorder. Tolerance to its antiseizure effect can appear within months.
Updated 2026-11-01
The figure shows diazepam, a benzodiazepine that occupies the same site, bound to the human GABA-A receptor (α1β2γ2) with GABA; no structure with clonazepam is available.
Mechanism of action
Clonazepam binds the benzodiazepine site of the GABA-A receptor and makes GABA open the chloride channel more often, which raises the threshold for seizures and calms panic. It is broken down mainly by reduction of its nitro group, with CYP3A taking part.
- Binds the benzodiazepine site of the GABA-A receptor
- GABA opens the chloride channel more often
- The seizure threshold rises and panic eases
Pharmacokinetics
- Absorption
- Absorbed quickly and almost completely by mouth
- Metabolism
- Nitro-reduction to 7-amino-clonazepam and further steps; CYP3A involved
- Half-life
- Typically 30 to 40 hours
Indications
- Seizures: Lennox-Gastaut syndrome, akinetic and myoclonic seizures, absence seizures not controlled by succinimides Epilepsy and seizures →
- Panic disorder, with or without agoraphobia Panic disorder →
Adverse effects
Common
- Drowsiness
- Poor coordination and unsteadiness
- Increased saliva and bronchial secretions
Contraindications
- Hypersensitivity to benzodiazepines
- Significant liver disease
- Acute narrow-angle glaucoma
Key interactions
- Opioids
- Profound sedation, respiratory depression, coma and death
- Alcohol and other central nervous system depressants
- Additive sedation and breathing depression
- Enzyme inducers (phenytoin, carbamazepine, phenobarbital, lamotrigine)
- Lower clonazepam levels
- CYP3A inhibitors such as oral antifungals
- Higher clonazepam levels
What is monitored
- Seizure frequency and signs of tolerance
- Mood and suicidal thoughts
- Secretions and swallowing in people with lung or swallowing problems
- Sedation and breathing
Administration and safety
- Given by mouth (tablets; orally disintegrating forms exist)
- Controlled medicine; tapered gradually because sudden withdrawal can trigger status epilepticus
Nursing care
- Before each dose, check level of alertness, breathing rate and oxygen saturation
- Ask about opioids, alcohol and other sedatives
- Prevent falls, especially in older adults (unsteadiness, confusion)
- Teach not to drive or drink alcohol and not to stop the medicine suddenly
- Ask the family to report new mood changes or thoughts of self-harm
Pregnancy and breastfeeding
Use late in pregnancy can cause sedation and withdrawal symptoms in the newborn, who is watched after birth.
Test yourself
Think of the answer, then tap the question to see it.
Which two very different conditions does clonazepam treat?
Certain seizures (myoclonic, akinetic, Lennox-Gastaut, refractory absences) and panic disorder.
What limits clonazepam as a long-term antiseizure medicine?
Tolerance: some patients lose the antiseizure effect within months.
Which liver condition contraindicates clonazepam?
Significant liver disease.
Related drugs
Related conditions
← Back to the class: Benzodiazepines
Educational content on how drugs work; not a prescribing guide and no substitute for a health professional's advice. No doses are given.
Sources: DailyMed - CLONAZEPAM tablet (DailyMed (U.S. National Library of Medicine), 2026); ATCDDD - ATC/DDD Index (WHO Collaborating Centre for Drug Statistics Methodology, 2026).
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Representative model, for educational purposes only.