What are the differences between Aplenzin (bupropion) and Wellbutrin (bupropion) for an adult patient with a history of depression?

Aplenzin vs Wellbutrin: Key Differences

Aplenzin and Wellbutrin are both bupropion formulations with identical active ingredients and equivalent efficacy for depression, but differ primarily in their salt formulation and dosing schedules—Aplenzin uses bupropion hydrobromide while Wellbutrin uses bupropion hydrochloride, requiring different milligram strengths to achieve the same therapeutic effect. 1

Formulation and Bioequivalence

• All bupropion formulations (IR, SR, XL) are bioequivalent in terms of systemic exposure to bupropion, meaning they deliver the same amount of active drug to your bloodstream 2

• Aplenzin contains bupropion hydrobromide salt, while Wellbutrin contains bupropion hydrochloride salt—this means Aplenzin 348 mg is equivalent to Wellbutrin XL 300 mg due to the different molecular weights of the salt forms 1

• Historical bioequivalence issues existed with some generic bupropion SR formulations, which were found not to be bioequivalent to brand-name Wellbutrin SR, requiring close monitoring when switching between formulations 1

Dosing Schedules and Administration

• Wellbutrin SR requires twice-daily dosing (150 mg twice daily for 300 mg total), with the first dose in the morning and second dose before 3 PM to minimize insomnia risk 1

• Wellbutrin XL and Aplenzin allow once-daily dosing (300 mg once daily in the morning), providing improved convenience and potentially better adherence 1

• The standard titration for SR formulation starts with 150 mg once daily for 3 days, then increases to 150 mg twice daily if tolerated 1

Clinical Efficacy and Tolerability

• Bupropion demonstrates equivalent efficacy across all formulations for major depressive disorder, with response rates similar to SSRIs and SNRIs (approximately 42-49% remission rates) 3, 2

• Bupropion has significantly lower rates of sexual dysfunction compared to SSRIs (decreased risk with bupropion versus trend toward increased risk with escitalopram and paroxetine), making it advantageous for patients concerned about this side effect 3, 2

• Bupropion is associated with minimal weight gain or even weight loss, unlike many other antidepressants, and has lower rates of sedation than SSRIs 3, 4

Safety Considerations (Identical Across Formulations)

• Maximum doses must not exceed 400 mg/day for SR or 450 mg/day for XL formulations to minimize seizure risk (approximately 0.1% at recommended doses) 1

• Absolute contraindications include seizure disorders, eating disorders (bulimia/anorexia), abrupt discontinuation of alcohol/benzodiazepines, and concurrent MAOI use or within 14 days of discontinuation 1

• Dose reductions are mandatory in hepatic impairment (maximum 150 mg daily in moderate-to-severe impairment) and renal impairment (50% dose reduction in moderate-to-severe impairment) 1

Clinical Decision-Making Algorithm

Choose Wellbutrin SR (twice daily) when:

• Patients need more flexible dosing due to side effects requiring dose adjustments 1
• Hepatic or renal impairment necessitates lower individual doses 1
• Cost is a primary concern (generic SR typically less expensive)

Choose Wellbutrin XL or Aplenzin (once daily) when:

• Adherence is a concern and simplified dosing would help 1
• Patient prefers convenience of once-daily administration 1
• Patient has no hepatic/renal impairment requiring dose splitting 1

Special Clinical Advantages

• Bupropion may be particularly beneficial for patients with depression characterized by low energy, apathy, or hypersomnia due to its activating dopaminergic/noradrenergic properties 1

• Patients attempting smoking cessation benefit from bupropion's dual indication, addressing both depression and nicotine dependence simultaneously (standard dose 150 mg twice daily starting 1-2 weeks before quit date) 1

• The combination of bupropion with SSRIs decreases depression severity more than SSRI augmentation with buspirone in patients failing monotherapy 1

Monitoring and Time to Effect

• Allow 6-8 weeks at adequate therapeutic doses before determining treatment response, though energy levels may improve within the first few weeks 1

• Close monitoring is required in the first 1-2 months, especially in patients under 24 years, due to increased risk of suicidal ideation (black box warning) 1

• Blood pressure and heart rate should be monitored periodically, especially in the first 12 weeks, as bupropion can cause elevations in both parameters 3, 1

Critical Pitfalls to Avoid

• Never administer the second dose of SR formulation after 3 PM—this significantly increases insomnia risk 1

• Do not switch between brand and generic formulations without close monitoring—historical bioequivalence issues may lead to loss of antidepressant effect 1

• Avoid premature discontinuation before 6-8 weeks unless significant adverse effects occur, as full therapeutic effect requires adequate time 1