What is the starting dose of Wellbutrin (bupropion)?

Starting Dose of Wellbutrin (Bupropion)

The starting dose of Wellbutrin (bupropion) is 150 mg once daily in the morning, which can be increased after 4 days to the target dose of 300 mg once daily for major depressive disorder. 1

Standard Dosing by Indication

Major Depressive Disorder (MDD)

• Initial dose: 150 mg once daily in the morning 1
• Titration: After 4 days, may increase to target dose of 300 mg once daily 1
• Alternative regimen: Some guidelines recommend starting at 37.5 mg every morning, then increasing by 37.5 mg every 3 days, with a maximum of 150 mg twice daily 2
• Administration: Take in the morning; may be taken with or without food 1
• Important: Swallow tablets whole—do not crush, divide, or chew 1

Smoking Cessation

• Days 1-3: 150 mg once daily 2
• Day 4 through 12 weeks: 150 mg twice daily if tolerated 2
• Maximum dose: 300 mg per day 2
• Timing: Initiate dosing 1-2 weeks prior to quitting smoking 2

Seasonal Affective Disorder (SAD)

• Initial dose: 150 mg once daily for 7 days 1
• Target dose: 300 mg once daily after the first week 1
• Timing: Initiate in autumn prior to symptom onset; continue through winter season 1

Special Population Dosing Adjustments

Hepatic Impairment

• Moderate to severe hepatic impairment (Child-Pugh 7-15): Maximum dose is 150 mg every other day 1
• Mild hepatic impairment (Child-Pugh 5-6): Consider reducing dose and/or frequency 1

Renal Impairment

• GFR <90 mL/min: Consider reducing dose and/or frequency 1

Elderly Patients

• Start with lower doses (approximately 50% of standard adult starting dose) due to increased risk of adverse drug reactions 2
• The 37.5 mg starting dose with gradual titration is particularly appropriate for elderly patients 2

Critical Safety Considerations

Seizure Risk Minimization

• Gradual dose escalation is essential to minimize seizure risk 1
• Seizure incidence is <1 per 1,000 at usual outpatient doses and <1 per 100 at usual inpatient doses 3
• Contraindicated in patients with seizure disorders, brain metastases, or conditions that lower seizure threshold 2

Timing to Avoid Insomnia

• Give second dose (if using twice-daily regimen) before 3 p.m. to minimize insomnia risk 2
• The activating properties of bupropion make morning dosing preferable 2

Drug Interactions

• MAO inhibitors: Allow at least 14 days between discontinuing an MAOI and starting bupropion, and vice versa 1
• Contraindicated with tamoxifen and in patients taking MAO inhibitors due to increased risk of hypertensive reactions 2

Expected Timeline for Response

• Onset of action: 2 weeks with full efficacy at 4 weeks 4
• Smoking cessation: Benefits observed within 7-12 weeks 2
• Maintenance treatment: Continue for several months or longer beyond acute response 1

Common Pitfalls to Avoid

• Do not start at full dose: Always begin at 150 mg daily to reduce seizure risk 1
• Do not exceed maximum doses: 300 mg/day for smoking cessation; 450 mg/day for immediate-release formulations (though Wellbutrin XL maximum is 300 mg/day) 2, 1
• Avoid in agitated patients: Bupropion is activating and can worsen agitation 2
• Monitor for neuropsychiatric symptoms: Although uncommon, watch for worsening depression, suicidal ideation, or behavioral changes, particularly in the first 1-2 weeks 2, 1