Wellbutrin SR Dosing
For major depressive disorder, start Wellbutrin SR at 150 mg once daily for 3 days, then increase to 150 mg twice daily (300 mg total daily dose), with a maximum dose of 400 mg per day. 1
Standard Dosing for Major Depressive Disorder
- Initial dose: 150 mg once daily in the morning for the first 3 days 1
- Maintenance dose: 150 mg twice daily (300 mg total daily) 1, 2
- Maximum dose: 400 mg per day (200 mg twice daily) 1
- Timing: Administer the second dose before 3 PM to minimize insomnia risk 1, 2
The American Family Physician recommends this titration schedule to minimize seizure risk while achieving therapeutic levels. 1 The gradual increase allows assessment of tolerability before reaching the full therapeutic dose. 1
Alternative Dosing for Smoking Cessation
- Standard dose: 150 mg twice daily (300 mg total) 1
- Initiation: Begin 1-2 weeks before target quit date 1
- Duration: 7-12 weeks of treatment 1
- Efficacy assessment: Evaluate response after 7-12 weeks 1
This indication may be particularly beneficial for patients with comorbid depression who want to quit smoking, addressing both conditions simultaneously. 1
Special Population Adjustments
Older Adults (≥55 years)
- Start with 37.5 mg once daily in the morning 1, 2
- Titrate by 37.5 mg every 3 days as tolerated 1, 2
- Maximum dose: 150 mg twice daily (300 mg total daily) 1, 2
- Second dose must be before 3 PM 1, 2
Lower starting doses minimize risk of adverse reactions in this population. 1
Hepatic Impairment
- Moderate to severe impairment: Maximum 150 mg daily (one tablet total) 1
Bupropion metabolism is significantly affected by hepatic dysfunction, requiring substantial dose reduction. 1
Renal Impairment
- GFR <90 mL/min: Reduce total daily dose by half 1, 2
- Close monitoring required as bupropion and metabolites accumulate with renal dysfunction 1, 2
Critical Safety Considerations
Absolute Contraindications
- Seizure disorders (bupropion lowers seizure threshold) 1, 2
- Bulimia or anorexia nervosa (increased seizure risk) 1, 2
- Concurrent MAOI use or within 14 days of discontinuing MAOIs 1
- Abrupt discontinuation of alcohol, benzodiazepines, barbiturates, or antiepileptic drugs 1
- Patients taking tamoxifen (may reduce tamoxifen efficacy) 1, 2
Maximum Dose Limits
- Never exceed 450 mg per day to minimize seizure risk 1
- For SR formulation specifically, maximum is 400 mg per day 1
The seizure risk increases substantially above recommended doses, making strict adherence to maximum dosing essential. 1
Monitoring Requirements
- Blood pressure at baseline and during titration (avoid in uncontrolled hypertension) 1, 2
- Suicidal ideation, especially in patients <24 years old 2
- Neuropsychiatric symptoms: agitation, anxiety, mood changes 1, 2
- Response assessment: Allow 6-8 weeks at adequate dose before determining treatment failure 1
Common Side Effects and Management
- Insomnia (most common): Ensure second dose is before 3 PM 1, 2
- Dry mouth, headache, nausea, anxiety 3
- Weight loss: Mean 0.5-1.0 kg at end of treatment 4
Insomnia and dry mouth occur significantly more frequently than placebo but are generally transient and resolve without intervention. 3
Important Clinical Pearls
- Bupropion has activating properties, making it ideal for patients with low energy, apathy, or hypersomnia 1
- Less sexual dysfunction compared to SSRIs 5, 6
- Monitor closely when switching between brand and generic formulations due to historical bioequivalence issues 1
- Energy levels may improve within the first few weeks, faster than other antidepressants 1