Bupropion Dosing for Weight Loss
Bupropion is not FDA-approved for weight loss, but when used for this purpose, the recommended dose is 300 mg daily (150 mg twice daily) of the sustained-release (SR) formulation, with careful dose titration to minimize side effects. 1
Dosing Protocol for Weight Loss
- Start with 150 mg once daily for the first week to minimize side effects 2
- Increase to the target dose of 150 mg twice daily (300 mg total) after the first week if well tolerated 1, 3
- Maximum recommended dose should not exceed 400 mg daily due to increased seizure risk 2
- Assess efficacy after 8-12 weeks; discontinue if significant weight loss (≥5%) is not achieved 1, 3
Evidence for Weight Loss Efficacy
- Clinical trials show modest weight loss with bupropion SR at 300 mg daily, with approximately 4.9% weight loss over 8 weeks compared to 1.3% with placebo 3
- In sustained-release formulation trials, 14% of participants lost >5 lbs at 300 mg/day and 19% at 400 mg/day, compared to 6% with placebo 4
- Long-term trials (up to 6 months) showed 23% of participants taking bupropion had weight loss ≥5 lbs compared to 11% with placebo 4
Formulation Considerations
- Sustained-release (SR) formulation is preferred for weight loss, administered as 150 mg twice daily 1, 2
- Extended-release (XL) formulation can be used as an alternative at 300 mg once daily in the morning 2
- Immediate-release formulation is not recommended for weight loss due to three-times-daily dosing requirement and increased risk of side effects 2, 5
Special Populations and Precautions
- For patients with moderate to severe hepatic impairment, reduce the total daily dose to 150 mg 2
- For patients with moderate to severe renal impairment, reduce the total daily dose by 50% 2
- Avoid use in patients with seizure disorders, eating disorders, or uncontrolled hypertension 1, 2
- Contraindicated during or within 14 days of MAOI use 1, 2
- Monitor blood pressure regularly as hypertension can occur in 2% of patients 4
Common Side Effects to Monitor
- Insomnia (20% vs 13% placebo) - administer the second dose before 3 PM to minimize this effect 4
- Decreased appetite (4% vs 1% placebo) - expected and may contribute to weight loss effect 4
- Dry mouth (20%) and headache (26%) are common but typically manageable 4
- Anxiety (7% vs 5% placebo) and agitation (2% vs <1% placebo) may occur 4
Combination Therapy Considerations
- Bupropion combined with naltrexone (as Contrave) is FDA-approved for weight management and may be more effective than bupropion alone 1, 6
- When used as part of Contrave, the recommended maintenance dose is 360 mg bupropion with 32 mg naltrexone daily 1
- For better results, combine bupropion with caloric restriction (approximately 1600 kcal/day balanced diet) 3
Monitoring and Follow-up
- Assess weight loss progress monthly for the first 3 months 1
- Discontinue if 5% weight loss is not achieved after 12 weeks of treatment at the target dose 1
- Monitor for neuropsychiatric adverse effects, especially in younger patients 2
- Regular blood pressure monitoring is essential as bupropion can cause hypertension 1, 4