Comparative Pharmacology
Head-to-head clinical analysis: WELLBUTRIN versus WELLBUTRIN SR.
Peer-Reviewed Evidence
Head-to-head clinical analysis: WELLBUTRIN versus WELLBUTRIN SR.
WELLBUTRIN vs WELLBUTRIN SR
Comparing the clinical profiles, pharmacokinetic behaviors, and safety indices of these two therapeutic agents.
Bupropion is a relatively selective inhibitor of the neuronal reuptake of norepinephrine and dopamine. It does not inhibit monoamine oxidase or the reuptake of serotonin.
Wellbutrin SR (bupropion) is an atypical antidepressant. Its mechanism of action is not fully understood, but it is thought to involve inhibition of dopamine and norepinephrine reuptake in the brain, with minimal effect on serotonin reuptake. It also acts as a nicotinic acetylcholine receptor antagonist.
Immediate-release: 100 mg orally twice daily initially; after 3 days, increase to 100 mg 3 times daily. Sustained-release: 150 mg orally once daily initially; after 3 days, increase to 150 mg twice daily. Extended-release: 150 mg orally once daily initially; after 3 days, increase to 300 mg once daily.
150 mg orally once daily, may increase to 150 mg twice daily after 3 days if needed. Maximum 300 mg/day.
None Documented
None Documented
Terminal half-life: 21 ± 6 hours (hydroxybupropion 24 ± 6 h, threohydrobupropion 37 ± 13 h, erythrohydrobupropion 33 ± 10 h); requires 5-8 days to reach steady state
Terminal half-life of bupropion is approximately 21 hours (±9 hours); for the active metabolite hydroxybupropion, half-life is ~20-27 hours. Steady state reached within 5-8 days.
Renal (87% as metabolites, 0.5% unchanged); fecal (10%)
Primarily renal (87% as bupropion and its metabolites, with 10% as unchanged drug); 10% fecal.
Category C
Category C
NDRI Antidepressant
NDRI Antidepressant