GlaxoSmithKline; available as generic bupropion IR and SR; generic bupropion XL received approval in 2006.
Major Depressive Disorder
Prevention of Seasonal Affective Disorder (Wellbutrin XL only)
Smoking cessation (Zyban only)
Wellbutrin is chemically unrelated to SSRI, tricyclic or other known antidepressants; mediated by noradrenergic and/or dopaminergic mechanisms.
XL: 150 mg and 300 mg tablets
SR: 100 mg, 150 mg, and 200 mg film-coated tablets
IR (original immediate release version): 75 mg and 100 mg tablets
Zyban: 150 mg purple tablets
XL beginning dose: 150 mg QAM; may increase to usual dose of 300 mg QAM if adequately tolerated after at least 4 days; maximum dose 450 mg QAM.
SR beginning dose: Start at 100 mg QAM, and gradually titrate to usual dose of 150 mg BID; maximum dose 200 mg BID.
Zyban: Begin two weeks before quit date at 150 mg QD, increase to 150 mg BID after 3 days.
Dose must be reduced in patients with kidney or liver impairment.
Most common (for Wellbutrin SR 300 mg/day) are: anorexia, dry mouth, rash, sweating, tinnitus, and tremor (>5% and > twice placebo rate).
Seizure risk at 300 mg/day or less is 0.1%, similar to risk with other ADs; seizure risk at 450 mg/day is about 0.4%, and at 600 mg/day almost 4%.
Black Box Warning: In clinical trials, SSRIs and SNRIs increased the risk of suicidality in children (from 2% to 4%). No actual suicides occurred in these trials.
Pregnancy Risk Category C
Luvox (fluvoxamine) inhibits the metabolism of bupropion, possibly increasing levels.
Wellbutrin can increase levels of a variety of antidepressants, most notably Effexor.
All four formulations are equally effective, and there is no demonstrated difference in risk of seizure; XL has a slight convenience advantage for the patient (once-daily dosing).