Buspirone is an anxiolytic agent, chemically and pharmacologically distinct from benzodiazepines, barbiturates, and other sedative/anxiolytic drugs. It is a serotonin 5-HT1A receptor partial agonist, indicated for the management of anxiety disorders. It lacks significant sedative, anticonvulsant, or muscle relaxant properties and has a low potential for abuse, dependence, or withdrawal syndrome, making it a preferred choice in the Indian context for Generalized Anxiety Disorder (GAD).
Adult: Initial dose: 5 mg two to three times daily (e.g., 10-15 mg/day). May be increased by 5 mg per day every 2-3 days as needed. Usual therapeutic range: 15-30 mg/day in divided doses. Maximum recommended dose: 60 mg/day.
Note: Administer orally with or without food, but consistency is important (always with or always without food to maintain steady bioavailability). Tablets should be swallowed whole with a glass of water. Do not crush or chew.
Buspirone exerts its anxiolytic effect primarily through selective, partial agonistic activity at presynaptic and postsynaptic serotonin 5-HT1A receptors in the brain. It reduces serotonin neurotransmission, which is thought to be overactive in anxiety states. Unlike benzodiazepines, it does not act on the GABA-A receptor complex.
Pregnancy: Category B: Animal studies have not shown risk, but no adequate, well-controlled studies in pregnant women. Use only if clearly needed. Consider risk-benefit.
Driving: May cause dizziness, drowsiness, or blurred vision. Patients should not drive or operate heavy machinery until they know how the drug affects them.
| Monoamine Oxidase Inhibitors (MAOIs) e.g., Phenelzine, Selegiline | Risk of hypertensive crisis; contraindicated. A 14-day washout period is required. | High |
| Strong CYP3A4 Inhibitors (e.g., Ketoconazole, Itraconazole, Clarithromycin, Ritonavir, Grapefruit juice) | Markedly increase buspirone plasma levels, increasing risk of adverse effects (dizziness, sedation). Dose reduction of buspirone is recommended. | High |
| Other CNS Depressants (e.g., Alcohol, Benzodiazepines, Opioids, Sedating Antihistamines) | Additive CNS depression, impaired alertness, and psychomotor performance. | Moderate |
| Serotonergic Drugs (e.g., SSRIs: Fluoxetine, Sertraline; SNRIs; TCAs; Tramadol; Triptans) | Increased risk of serotonin syndrome (agitation, hyperreflexia, hyperthermia). | Moderate |
| Haloperidol | May increase serum haloperidol levels, increasing risk of EPS. | Moderate |
| Digoxin | Buspirone may increase digoxin levels; monitor digoxin levels. | Moderate |
| Rifampicin (CYP3A4 inducer) | Decreases buspirone plasma levels, potentially reducing efficacy. | Moderate |