Diazepam is a long-acting benzodiazepine derivative with potent anxiolytic, sedative, hypnotic, skeletal muscle relaxant, anticonvulsant, and amnestic properties. It acts centrally by enhancing the effect of the inhibitory neurotransmitter gamma-aminobutyric acid (GABA) at the GABA-A receptor. In the Indian context, it is a widely prescribed and cost-effective agent for anxiety, insomnia, and muscle spasm, but is strictly regulated under Schedule H1 and the NDPS Act due to high abuse potential.
Adult: Anxiety: 2-10 mg orally, 2-4 times daily. Muscle spasm: 2-10 mg orally, 3-4 times daily. Alcohol withdrawal: 10 mg, 3-4 times in first 24 hours, then reduce. Seizures: 2-10 mg, 2-4 times daily.
Note: Take orally with or without food. To minimize daytime drowsiness, take at bedtime if prescribed for insomnia. For anxiety/muscle spasm, divide daily dose. Tablets can be split. DO NOT crush or chew sustained-release formulations (if available). Avoid abrupt discontinuation.
Diazepam potentiates the inhibitory effects of GABA, the major inhibitory neurotransmitter in the CNS. It binds to a specific site (the benzodiazepine binding site) on the GABA-A receptor, a ligand-gated chloride channel. This binding increases the frequency of chloride channel opening events when GABA is bound, leading to enhanced chloride ion influx into the neuron, hyperpolarization, and reduced neuronal excitability.
Pregnancy: Category D (US FDA). Crosses placenta. Risk of congenital malformations (cleft lip/palate) if used in first trimester. Risk of neonatal flaccidity, respiratory depression, and withdrawal syndrome ('floppy infant syndrome') if used near term. Use only if clearly needed and potential benefit justifies risk. Contraindicated for routine use.
Driving: IMPAIRED ABILITY. Causes drowsiness, dizziness, blurred vision, and impaired motor coordination. Patients must NOT drive or operate heavy machinery, especially during initial therapy and dose adjustments.
| Alcohol | Profound additive CNS and respiratory depression | Major |
| Opioids (e.g., Codeine, Tramadol) | Increased risk of profound sedation, respiratory depression, coma, death | Major |
| Other CNS Depressants (Antipsychotics, Antihistamines, Barbiturates) | Additive CNS depression | Major |
| CYP3A4 Inhibitors (e.g., Ketoconazole, Clarithromycin, Ritonavir) | Increased diazepam levels, enhanced effects | Moderate |
| CYP2C19/3A4 Inducers (e.g., Rifampicin, Carbamazepine, Phenytoin) | Decreased diazepam levels, reduced efficacy | Moderate |
| Sodium Oxybate | Synergistic CNS depressant effect | Major |
| Probenecid | May delay onset but prolong duration of action | Moderate |
| Theophylline | May antagonize sedative effect of diazepam | Moderate |