Clonazepam (Klonopin)
Clonazepam is a long-acting benzodiazepine licensed for epilepsy and panic disorder. Its long half-life gives smooth coverage, but sustained use produces tolerance, dependence, and a withdrawal syndrome that can include seizures on abrupt cessation.
01 Overview
Clonazepam enhances GABA-A signalling with a long duration of action, making it useful for seizure disorders and panic disorder where steady blood levels are desirable. It also has some serotonergic activity thought to contribute to its anti-panic effect.
As with all benzodiazepines, regular use leads to tolerance and physical dependence. Abrupt discontinuation can precipitate withdrawal seizures, and combination with opioids or alcohol produces additive respiratory depression. Cognitive and amnestic effects occur dose-dependently.
02 Mechanism
Positive allosteric modulator of the GABA-A receptor with a long half-life; enhances neuronal inhibition producing anticonvulsant, anxiolytic and sedative effects.
03 Dosing
| Tier | Dose | Route | Notes |
|---|---|---|---|
| Light | 0.25–0.5 mg | Oral | Low starting dose for panic disorder. |
| Common | 0.5–1 mg | Oral | Common per-dose range. |
| Therapeutic (daily) | 0.5–4 mg/day | Oral | Epilepsy may use higher divided daily totals under supervision. |
04 Effects
| Effect | Magnitude | Evidence | |
|---|---|---|---|
| AnticonvulsantReduces seizure frequency across several epilepsy types. | Clinical | ||
| Anxiolysis / anti-panicEffective in panic disorder with sustained coverage. | Clinical | ||
| SedationDose-dependent drowsiness and calm. | Clinical |
05 Side effects
| Effect | Severity | Frequency | Evidence | Countermeasures |
|---|---|---|---|---|
| Dependence and withdrawalTolerance and physical dependence; abrupt cessation can cause rebound symptoms and seizures. | Severe | Common with regular use | Clinical | |
| Respiratory depressionAdditive respiratory and CNS depression with opioids or alcohol. | Life-threatening | Uncommon alone, higher with CNS depressants | Clinical | |
| Cognitive impairment and sedationDrowsiness, psychomotor slowing and memory impairment. | Moderate | Common | Clinical |