What is the starting dose of Wellbutrin (bupropion) for adults?

Starting Dose of Wellbutrin (Bupropion)

For major depressive disorder in adults, start with bupropion SR 150 mg once daily for the first 3 days, then increase to 150 mg twice daily (300 mg total daily dose). 1

Standard Adult Dosing by Formulation

Bupropion SR (Sustained Release)

• Initial dose: 150 mg once daily in the morning for 3 days 1
• Maintenance dose: 150 mg twice daily (300 mg total daily) after the initial 3-day period 1
• Timing: First dose in the morning, second dose before 3 PM to minimize insomnia risk 1
• Maximum dose: 400 mg per day 1

Bupropion XL (Extended Release)

• Initial dose: 150 mg once daily in the morning for 1 week 2
• Maintenance dose: 300 mg once daily 1, 2
• Maximum dose: 450 mg per day 1

Special Population Dosing Adjustments

Older Adults (≥55 years)

• Start lower and go slower: Begin with 37.5 mg once daily in the morning 1, 3
• Titration: Increase by 37.5 mg every 3 days as tolerated 1, 3
• Maximum dose: 150 mg twice daily (300 mg total daily) 1, 3
• Rationale: Older adults have increased risk of adverse reactions requiring more conservative dosing 1

Hepatic Impairment

• Moderate to severe hepatic impairment: Do not exceed 150 mg daily (one tablet total) 1

Renal Impairment

• Moderate to severe renal impairment (GFR <90 mL/min): Reduce total daily dose by half 1, 3
• Rationale: Bupropion and its metabolites are cleared renally and may accumulate 3

Critical Safety Considerations

Absolute Contraindications

• Seizure disorders: Bupropion lowers seizure threshold and should be avoided entirely 1, 3
• Eating disorders (bulimia, anorexia nervosa): Increased seizure risk contraindicates use 3
• MAOIs: Avoid within 14 days of discontinuing MAOIs 1
• Concurrent tamoxifen use: May reduce tamoxifen efficacy 3

Seizure Risk Minimization

• Maximum daily dose: Never exceed 450 mg per day to minimize seizure risk 1
• Dose-related phenomenon: Seizure incidence is <0.1% at recommended doses (300 mg/day for smoking cessation) but increases with higher doses 4, 5
• Individual dose limits: No single dose should exceed 150 mg for SR formulation 4

Monitoring Requirements

Initial and Ongoing Monitoring

• Blood pressure: Check at baseline and during titration, as bupropion should be avoided in uncontrolled hypertension 1, 3
• Neuropsychiatric symptoms: Monitor for suicidal ideation (especially in patients <24 years), agitation, anxiety, and mood changes 1, 3
• Response assessment: If no response after 6-8 weeks at adequate dose, consider alternative treatment 1

Common Pitfalls and Management

Insomnia (Most Common Side Effect)

• Prevention strategy: Ensure second SR dose is before 3 PM; take XL formulation in morning only 1, 3
• Generally transient: Often resolves without intervention 4
• Management if persistent: Consider dose reduction 4

Other Common Side Effects

• Dry mouth, headache, nausea, anxiety: Occur more frequently than placebo but are generally manageable 4
• Agitation: Monitor closely as bupropion has activating properties 1

Clinical Context for Formulation Selection

Bupropion SR offers more flexible dosing for patients requiring dose adjustments due to side effects or organ impairment, while XL provides once-daily convenience for patients who can tolerate the standard maintenance dose 1. Both formulations are bioequivalent under steady-state conditions 2, 6.