What is the recommended dosage of bupropion (Zyban) for smoking cessation?

Bupropion Dosage for Smoking Cessation

The recommended dosage of bupropion SR (Zyban) for smoking cessation is 150 mg once daily for the first 3 days, followed by 150 mg twice daily (300 mg total) for 7-12 weeks, starting 1-2 weeks before the target quit date. 1

Dosing Schedule and Duration

• Initial dose: 150 mg once daily for 3 days
• Maintenance dose: 150 mg twice daily (300 mg total)
• Start timing: Begin 1-2 weeks before planned quit date (typically day 8 of treatment)
• Standard duration: 7-12 weeks
• Extended therapy: May be continued up to 6 months to 1 year for promoting continued cessation in successful quitters 1

Clinical Efficacy

Bupropion SR significantly improves long-term abstinence rates compared to placebo. Clinical trials demonstrate that bupropion SR increases 12-month abstinence rates by approximately 9-10 percentage points compared to placebo 2. In a head-to-head comparison study, bupropion SR showed superior efficacy to nicotine patch alone (30.3% vs 16.4% abstinence at 12 months) 3.

Contraindications

Bupropion SR is contraindicated in patients with:

• Seizure disorders or risk factors for seizures
• Current use of MAO inhibitors
• Concurrent tamoxifen therapy
• Closed-angle glaucoma
• History of eating disorders
• History of bipolar disorder
• Severe hepatic cirrhosis 1, 2

Side Effects and Management

Common side effects include:

• Insomnia (most common)
• Dry mouth
• Headache
• Nausea
• Anxiety 1, 4

Most side effects are transient and resolve without intervention. If needed, dose reduction can help manage persistent side effects 4.

Special Considerations

• Seizure risk: The risk of seizure is approximately 0.1% at the recommended dose. Maintain the maximum daily dose at 300mg to minimize this risk 4
• Weight management: Bupropion may help reduce weight gain associated with smoking cessation 1, 3
• Hepatic/renal impairment: Consider dose reduction in patients with moderate to severe hepatic or renal impairment 1
• Psychiatric monitoring: Monitor for development or worsening of neuropsychiatric symptoms, particularly in patients with psychiatric history 1

Combination Therapy

Combining bupropion SR with nicotine replacement therapy (NRT) may enhance efficacy for patients who have difficulty quitting with monotherapy alone. While combination therapy showed higher abstinence rates (35.5%) compared to bupropion alone (30.3%) in one study, the difference was not statistically significant 3. However, this approach may be considered for patients with significant nicotine dependence or previous failed quit attempts 1.

Important Clinical Pitfalls

• Seizure threshold: Avoid in patients with seizure risk factors and adhere strictly to dosing recommendations
• Drug interactions: Screen for potential interactions, particularly with medications that lower seizure threshold
• Patient selection: Evidence for effectiveness is primarily in medium to heavy smokers (15+ cigarettes per day) receiving behavioral support 1
• Adherence monitoring: Approximately 35% of patients may discontinue medication; emphasize the importance of completing the full treatment course 3
• Psychiatric symptoms: Carefully monitor for mood changes, depression, or suicidal ideation, especially during the first few weeks of treatment 1