Zyban (Bupropion) for Smoking Cessation: Dosage and Treatment Plan
The standard dosing regimen for Zyban is 150 mg once daily for 3 days, then 150 mg twice daily (300 mg total per day) for 7-12 weeks, starting 1-2 weeks before the target quit date. 1, 2
Dosing Schedule
Initiation and Titration:
- Start with 150 mg once daily for the first 3 days 1, 2
- Increase to 150 mg twice daily (300 mg total) if tolerated 3, 1
- Begin treatment 1-2 weeks before the target quit date to establish therapeutic drug levels 1, 2
- The maximum daily dose should not exceed 300 mg for smoking cessation to minimize seizure risk 1, 2
Treatment Duration:
- Continue for 7-12 weeks total 3, 1, 2
- Assess efficacy at the end of this period; if no significant progress toward abstinence by week 7-12, reassess treatment 1, 2
Efficacy and Expected Outcomes
Bupropion is highly effective for smoking cessation, improving 12-month sustained abstinence rates by approximately 9-10 percentage points compared to placebo. 3, 4
- Quit rates increase from approximately 11-12% with placebo to 19-23% with bupropion at one year 2, 5, 6
- The efficacy appears independent of its antidepressant effect 3, 2
- Bupropion reduces withdrawal symptom severity 3, 1
- Evidence is strongest for medium to heavy smokers (≥15 cigarettes per day) receiving behavioral support 3
Special Population Dosing Adjustments
Hepatic Impairment:
Renal Impairment:
Older Adults:
- Start with 37.5 mg every morning, then gradually increase by 37.5 mg every 3 days as tolerated 1
- Maximum dose of 150 mg twice daily (300 mg total) 1
- Administer the second dose before 3 p.m. to minimize insomnia 1
Absolute Contraindications
Do not prescribe bupropion in patients with:
- Any seizure disorder or history of seizures 1, 2, 4, 7
- Current or history of eating disorders (bulimia, anorexia nervosa) due to increased seizure risk 1, 4, 7
- Concurrent MAOI use or within 14 days of discontinuing MAOIs 1, 2, 4
- Severe hepatic cirrhosis 4
- History of bipolar disorder 4
- Hypersensitivity to bupropion or its metabolites 4
Safety Monitoring and Adverse Effects
Common Side Effects (generally transient):
- Insomnia and dry mouth are most common, occurring significantly more than placebo 8, 6
- Headache, nausea, and anxiety also reported 8, 7
- These typically resolve without intervention or with dose reduction 8
Serious Adverse Effects (rare but critical):
- Seizure risk: approximately 1 in 1,000 (0.1%) when properly screened 3, 2, 4, 8
- Anaphylactic/hypersensitivity reactions: 1 in 1,000 to 1 in 10,000 3, 2, 4
Required Monitoring:
- Monitor for neuropsychiatric adverse effects, especially in patients younger than 24 years (hostility, agitation, depressed mood, suicidal thoughts) 1, 2
- Monitor blood pressure; avoid in patients with uncontrolled hypertension 1, 2
- Obtain psychiatric history and assess suicide risk before prescribing 2
Behavioral Support Integration
Bupropion should be combined with behavioral counseling for optimal outcomes. 2, 4
- Published trials demonstrating efficacy included behavioral support 3, 2
- Comprehensive programs with individualized counseling plus pharmacotherapy can increase 6-month cessation rates from 6.8% to 21.3% compared to verbal advice alone 2
Clinical Pearls
Bupropion may be particularly beneficial for patients with comorbid depression who want to quit smoking, addressing both conditions simultaneously. 1, 2
- Weight gain mitigation: Bupropion reduces weight gain associated with smoking cessation (mean gain of 1.5-2.3 kg vs 2.9 kg with placebo) 5, 6
- Combination therapy: Bupropion plus nicotine patch shows higher abstinence rates (35.5%) than either alone, though not statistically superior to bupropion alone (30.3%) 6
- Varenicline is superior to bupropion (28% vs 19% quit rates), but bupropion remains first-line when varenicline is contraindicated or not tolerated 2
- Cost-effectiveness: Estimated cost per life-year saved is approximately £1000 or $1500 4