Comparative Pharmacology
Head-to-head clinical analysis: WELLBUTRIN SR versus WELLBUTRIN XL.
Peer-Reviewed Evidence
Head-to-head clinical analysis: WELLBUTRIN SR versus WELLBUTRIN XL.
WELLBUTRIN SR vs WELLBUTRIN XL
Comparing the clinical profiles, pharmacokinetic behaviors, and safety indices of these two therapeutic agents.
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.
Bupropion is a dopamine and norepinephrine reuptake inhibitor; its mechanism in smoking cessation is unknown.
150 mg orally once daily, may increase to 150 mg twice daily after 3 days if needed. Maximum 300 mg/day.
150 mg orally once daily; may increase to 300 mg once daily after 4 days, with maximum 300 mg/day.
None Documented
None Documented
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.
21 ± 9 hours (terminal half-life of bupropion); clinical context: steady-state reached in 5-6 days.
Primarily renal (87% as bupropion and its metabolites, with 10% as unchanged drug); 10% fecal.
Renal (87% as metabolites, 0.5% as parent drug) and fecal (10%).
Category C
Category C
NDRI Antidepressant
NDRI Antidepressant