bupropion

Bupropion is an atypical antidepressant also used as a smoking cessation aid. It is sold under brand names such as Wellbutrin for depression and Zyban for helping people quit smoking. It is classified pharmacologically as a norepinephrine-dopamine reuptake inhibitor (NDRI).

Bupropion increases the synaptic levels of norepinephrine and dopamine by inhibiting their reuptake. It has relatively weak effects on serotonin and, in addition, may act as a noncompetitive antagonist at certain nicotinic acetylcholine receptors, which is believed to contribute to its smoking cessation effects. The drug is generally associated with a lower incidence of sexual side effects compared with many other antidepressants. It is metabolized in the liver to an active metabolite, hydroxybupropion, and has a half-life that supports once- or twice-daily dosing depending on the formulation.

Bupropion is indicated for major depressive disorder and seasonal affective disorder, and is also approved for smoking cessation in adults. It is available in immediate-release, sustained-release (SR), and extended-release (XL) formulations. Dosing commonly starts at 150 mg once daily for several days, then increases to 150 mg twice daily, with a maximum of 450 mg per day. For smoking cessation, a typical regimen begins with 150 mg once daily for a few days, then 150 mg twice daily for 7 to 12 weeks.

Safety considerations include contraindications in individuals with a seizure disorder, bulimia or anorexia nervosa, or concurrent or recent use of monoamine oxidase inhibitors. It should be used with caution in patients with a history of eating disorders, severe head injury, or abrupt alcohol withdrawal. Common adverse effects include insomnia, dry mouth, headache, nausea, and dizziness; there is a higher seizure risk at higher doses or in predisposed individuals.