Bupropion is an atypical antidepressant and smoking cessation aid, chemically unrelated to SSRIs, SNRIs, or TCAs. It acts primarily as a norepinephrine-dopamine reuptake inhibitor (NDRI) with minimal serotonergic activity. In India, it is widely used for major depressive disorder (MDD) and as an aid for smoking cessation. The 300mg strength is a standard therapeutic dose, often initiated after a titration period.
Adult: MDD: Initial: 150mg SR once daily in the morning. After 3 days, may increase to 150mg SR twice daily (at least 8 hours apart). Target dose: 300mg/day (as 150mg SR BID). Max: 450mg/day. Smoking Cessation: Start 150mg SR once daily for 3 days, then 150mg SR BID. Continue for 7-12 weeks. Doses >300mg/day are not recommended for smoking cessation.
Note: Swallow SR tablet whole; do not crush, split, or chew. Take in the morning and, if on BID dosing, in the early afternoon (at least 8 hours after first dose) to minimize risk of insomnia. Can be taken with or without food. Taking with food may reduce gastrointestinal upset.
Bupropion is a weak but relatively selective inhibitor of the neuronal reuptake of norepinephrine and dopamine, with minimal effect on the reuptake of serotonin. It does not inhibit monoamine oxidase. Its antidepressant and smoking cessation effects are mediated through this enhancement of noradrenergic and dopaminergic neurotransmission in the central nervous system.
Pregnancy: Pregnancy Category C (US FDA). Animal studies showed fetal risks. No adequate, well-controlled studies in humans. Use only if potential benefit justifies potential fetal risk. Indian National Formulary advises caution. Consider risks of untreated depression.
Driving: May cause dizziness, visual disturbances, or impair judgment. Patients should not drive or operate heavy machinery until they know how the medication affects them.
| Monoamine Oxidase Inhibitors (MAOIs) - Phenelzine, Selegiline | Risk of hypertensive crisis, serotonin syndrome. | Contraindicated |
| Other antidepressants (SSRIs, TCAs, Venlafaxine) | Increased risk of seizures, serotonin syndrome. | Major |
| Antipsychotics (e.g., Risperidone, Haloperidol) | May lower seizure threshold; bupropion may increase antipsychotic levels via CYP2D6 inhibition. | Moderate |
| Beta-blockers (e.g., Metoprolol) | Bupropion may increase levels of CYP2D6 substrates like metoprolol, potentiating bradycardia and hypotension. | Moderate |
| Tamoxifen | Bupropion (CYP2D6 inhibitor) may reduce conversion of tamoxifen to its active metabolite, endoxifen, potentially reducing efficacy. | Major |
| Clopidogrel | Theoretical risk of reduced activation of clopidogrel (a prodrug) via CYP2B6 competition. | Moderate |
| Theophylline | Increased risk of seizures. | Major |
| Alcohol | Increases seizure risk; may alter seizure threshold. Avoid binge drinking. | Major |
Same composition (Bupropion (300mg)), different brands: