Clonazepam is a high-potency, long-acting benzodiazepine derivative primarily used as an anticonvulsant and anxiolytic. It acts as a positive allosteric modulator of the GABA-A receptor, enhancing inhibitory neurotransmission in the central nervous system. In the Indian context, it is a Schedule H1 drug, requiring strict prescription control due to its high potential for dependence and abuse.
Adult: Epilepsy: Initial: 0.5 mg at night, increase by 0.5 mg every 3 days. Maintenance: 1-4 mg/day in divided doses (max 20 mg/day). Panic Disorder: Initial: 0.25 mg twice daily, increase to 1 mg/day. Max: 4 mg/day.
Note: Take with or without food. Swallow tablet whole with water. For panic disorder, divided doses (BID/TID) are preferred. For epilepsy, dosing schedule depends on seizure pattern. Do not crush or chew. Do not stop abruptly; taper gradually over weeks to months.
Clonazepam binds to a specific, high-affinity site (distinct from the GABA binding site) on the GABA-A receptor complex, a ligand-gated chloride channel. This binding increases the frequency of chloride channel opening events in response to GABA, leading to hyperpolarization of the neuronal membrane and reduced neuronal excitability.
Pregnancy: Pregnancy Category D (US FDA). Evidence of human fetal risk. Use only if potential benefit justifies risk. Associated with neonatal flaccidity, respiratory problems, and withdrawal symptoms ('floppy infant syndrome'). Avoid especially in first trimester.
Driving: IMPAIRED ABILITY. Causes drowsiness, dizziness, and impaired coordination. Patients must not drive or operate machinery until individual response is known, especially during dose initiation and titration.
| Alcohol / CNS Depressants (Opioids, Barbiturates) | Profound additive CNS depression, respiratory depression, sedation, death risk. | Major |
| Enzyme Inhibitors (Ketoconazole, Itraconazole, Fluconazole, Clarithromycin, Erythromycin, Ritonavir) | Increased clonazepam levels and prolonged effects. | Major |
| Enzyme Inducers (Phenytoin, Carbamazepine, Rifampicin, Phenobarbital) | Decreased clonazepam levels, reduced efficacy. | Moderate |
| Sodium Valproate / Valproic Acid | Potential for increased sedation and absence status. | Moderate |
| Probenecid | May inhibit glucuronide conjugation, increasing clonazepam levels. | Moderate |
| Levodopa | Clonazepam may reduce therapeutic effect of levodopa in Parkinson's. | Moderate |
| Selective Serotonin Reuptake Inhibitors (SSRIs) | Variable interaction; may increase sedation. | Moderate |
Same composition (Clonazepam (0.5mg)), different brands: