Is single daily dosing of Wellbutrin (Bupropion) SR recommended?

Single Daily Dosing of Wellbutrin SR

Single daily dosing of Wellbutrin SR is not recommended according to the FDA drug label, which specifies a twice-daily dosing regimen for the sustained-release (SR) formulation. 1

Proper Dosing of Bupropion Formulations

Wellbutrin SR (Sustained-Release)

• Recommended dosing: 150 mg twice daily 1
• Maximum daily dose: 300 mg (divided into two doses) 1
• Doses should be separated by at least 8 hours to minimize seizure risk 1

Alternative Formulations

• Immediate-release (IR): Three times daily dosing 2
• Extended-release (XL): Once daily dosing in the morning 1
  • XL formulation is specifically designed for once-daily administration
  • Starting dose: 150 mg once daily in the morning
  • Target dose: 300 mg once daily in the morning

Risks of Inappropriate Dosing

Seizure Risk

• Bupropion carries a dose-dependent seizure risk of approximately 0.1% 3
• Risk increases when exceeding recommended doses or with improper dosing intervals 1
• Gradual dose increases are essential to minimize seizure risk 1

Adherence Concerns

• Research shows adherence decreases with multiple daily doses 4:
  • 15% nonadherence with once-daily dosing
  • 37% nonadherence with twice-daily dosing
  • 65% nonadherence with thrice-daily dosing

Clinical Considerations

Efficacy

• Clinical studies have specifically evaluated the SR formulation at twice-daily dosing 5
• While one older study suggested once-daily SR might be effective 5, this is not supported by the FDA-approved labeling 1

Pharmacokinetics

• SR formulation is designed for twice-daily administration to maintain therapeutic blood levels 1
• Single daily dosing of SR formulation may result in:
  • Suboptimal blood levels in latter part of day
  • Increased peak concentrations that could raise side effect risk

Side Effects

• Common side effects of bupropion SR include insomnia, headache, dry mouth, and anxiety 6
• Insomnia risk may increase if the second dose is taken too late in the day 3
• The American College of Physicians recommends taking the second daily dose before 3 p.m. to minimize insomnia risk 3

Recommendations for Patients Seeking Once-Daily Dosing

If once-daily dosing is strongly preferred by a patient:

1. Consider switching to bupropion XL (extended-release) formulation which is specifically designed and FDA-approved for once-daily dosing 1
2. When switching from SR to XL, maintain the same total daily dose when possible 1
3. Administer bupropion XL in the morning to minimize insomnia risk 1

Conclusion

For patients requiring bupropion therapy who prefer once-daily dosing, the extended-release (XL) formulation should be used rather than attempting once-daily dosing with the SR formulation. This approach aligns with FDA recommendations and optimizes both efficacy and safety.