What is the recommended dosing regimen for Zyban (bupropion hydrochloride) for smoking cessation?

Zyban Dosing for Smoking Cessation

For smoking cessation, start Zyban (bupropion) at 150 mg once daily in the morning for 3 days, then increase to 150 mg twice daily (maximum 300 mg/day) for 7-12 weeks, beginning 1-2 weeks before the target quit date. 1

Standard Dosing Regimen

The evidence-based protocol is straightforward:

• Days 1-3: 150 mg orally once daily (morning dose)
• Day 4 through 7-12 weeks: 150 mg orally twice daily if tolerated
• Maximum daily dose: 300 mg per day
• Timing: Initiate dosing 1-2 weeks prior to the target quit date 1, 2, 3

Maintain at least 6 hours between doses to minimize seizure risk 4. The FDA drug label emphasizes that no single dose should exceed 150 mg 4.

Treatment Duration

• Standard duration: 7-12 weeks 1
• Extended therapy: May be continued for 6 months to 1 year to promote continued cessation, though longer periods should be avoided if possible 1

The NCCN guidelines note that therapy may be extended beyond the initial 12 weeks while attempting to avoid unnecessarily prolonged treatment 1.

Combination Therapy

Bupropion can be combined with nicotine replacement therapy (NRT) 1, 2, 3. The dosing remains the same when used in combination. High-certainty evidence shows bupropion plus NRT may provide superior quit rates compared to NRT alone, though the evidence for this combination versus bupropion alone shows imprecision 5, 6.

Critical Safety Considerations

Absolute contraindications that must be screened for:

• Seizure disorders or seizure risk factors (stroke, brain metastases, head trauma) 1
• Current or prior diagnosis of bulimia or anorexia nervosa 4
• Concurrent MAO inhibitor use (increased hypertensive reaction risk) 1
• Abrupt discontinuation of alcohol or sedatives (alters seizure threshold) 4
• Closed-angle glaucoma 1

The seizure risk with bupropion is approximately 0.1% (1 in 1,000) when used at recommended doses 7, 8.

Special Populations

Hepatic impairment:

• Severe cirrhosis: Maximum 75 mg once daily 4
• Mild-to-moderate cirrhosis: Use reduced frequency and/or dose 4

Renal impairment: Use with caution; consider reduced frequency and/or dose 4

Monitoring Requirements

Monitor for neuropsychiatric symptoms including depression, suicidal ideation, hostility, agitation, and behavioral changes, particularly in the first few weeks 1. The FDA removed the black box warning for neuropsychiatric events in 2016 after the EAGLES trial showed no significant increase in these events compared to placebo 1, 9.

Common Adverse Events

The most frequent side effects are:

• Insomnia (most common—avoid bedtime dosing) 1, 10, 8
• Dry mouth 10, 8
• Headache 10
• Nausea 10

These are generally transient and can be managed by temporary dose reduction or short-term use of sedative-hypnotics (usually not needed beyond the first week) 4.

Efficacy Context

Bupropion approximately doubles the odds of smoking cessation compared to placebo, with 12-month abstinence rates of 18-30% versus 6-16% for placebo 11, 10, 5, 6. However, varenicline demonstrates superior efficacy (RR 0.71-0.73 favoring varenicline) 5, 6, 12, while bupropion shows similar effectiveness to single-form NRT 5, 6.

Key Clinical Pitfalls

• Do not combine with other bupropion-containing products (Wellbutrin SR, Wellbutrin XL) 4
• Do not exceed 150 mg per single dose to maintain seizure risk below 0.1% 4, 8
• Screen carefully for seizure risk factors before prescribing 8
• Advise patients to minimize or avoid alcohol due to altered seizure threshold and potential reduced tolerance 4
• Dose escalation should not exceed 100 mg/day in a 3-day period 4