What is the recommended dosage and treatment guidelines for Aplenzin (bupropion hydrochloride) in patients with major depressive disorder or seasonal affective disorder?

Aplenzin (Bupropion Hydrochloride) Dosing and Treatment Guidelines

Major Depressive Disorder (MDD)

Start Aplenzin at 150 mg once daily in the morning, then increase to the target dose of 300 mg once daily after 4 days. 1

Key Dosing Parameters

• Initial dose: 150 mg once daily in the morning 1
• Target dose: 300 mg once daily (reached after 4 days) 1
• Administration: Swallow whole; do not crush, divide, or chew. May be taken with or without food 1
• Maximum dose: 450 mg/day (though standard target is 300 mg for extended-release formulations) 2

Treatment Duration

• First episode of MDD: Continue treatment for 4 to 9 months after achieving satisfactory response 3
• Recurrent depression (≥2 episodes): Consider years to lifelong maintenance therapy 3
• Acute treatment phase: Requires several months or longer beyond initial response 1

Monitoring Requirements

Begin monitoring within 1 to 2 weeks of initiation, focusing on suicidal thoughts, agitation, irritability, and unusual behavioral changes. 3

• The risk for suicide attempts is greatest during the first 1 to 2 months of treatment 3
• Monitor for therapeutic response and adverse effects regularly 3
• If inadequate response by 6 to 8 weeks, modify treatment (response rate may be as low as 50%) 3

Seasonal Affective Disorder (SAD)

For SAD prevention, start at 150 mg once daily, increase to 300 mg once daily after 7 days, and initiate treatment in autumn before symptom onset. 1

SAD-Specific Dosing

• Initial dose: 150 mg once daily 1
• Target dose: 300 mg once daily after 7 days 1
• Timing: Begin in autumn, prior to onset of depressive symptoms 1
• Duration: Continue through winter season 1
• Discontinuation: Taper in early spring by reducing to 150 mg once daily before stopping 1

Special Population Adjustments

Hepatic Impairment

• Moderate to severe (Child-Pugh 7-15): Maximum 150 mg every other day 1
• Mild (Child-Pugh 5-6): Consider reducing dose and/or frequency 1

Renal Impairment

• GFR <90 mL/min: Consider reducing dose and/or frequency 1

Selection Rationale

Choose bupropion based on adverse effect profile, cost, and patient preferences rather than superior efficacy, as all second-generation antidepressants show equivalent effectiveness. 3

Advantages of Bupropion

• Significantly lower rates of sexual dysfunction compared to fluoxetine and sertraline 3
• Minimal anticholinergic effects 2
• Less likely to cause orthostatic hypotension than tricyclics 2
• May be less likely to provoke mania than serotonergic antidepressants 4
• Useful in atypical depression and treatment-resistant cases 2

Common Adverse Effects

• Insomnia and nervousness (most common) 4, 2
• Dry mouth 5, 2
• Headache 6
• Nausea (less common than with SSRIs) 4
• Delayed hypersensitivity reactions (urticaria, pruritus) can occur 2+ weeks after initiation, particularly in males aged 17-40 5

Critical Safety Considerations

Seizure Risk

Bupropion lowers seizure threshold; avoid in patients with epilepsy or predisposing factors for seizures. 1, 2

• Seizure risk is dose-dependent; overdoses ≥2.7g can cause seizures, encephalopathy, and cardiovascular effects 7
• When maintained at ≤450 mg/day in divided doses, seizure rate is comparable to other antidepressants 2

Drug Interactions

• MAOI contraindication: Allow 14 days between discontinuing MAOI and starting bupropion, and vice versa 1
• CYP2D6 inhibition: Exercise caution when co-prescribing with drugs metabolized by CYP2D6 6, 4
• Avoid combining with drugs that lower seizure threshold 6

Discontinuation

When stopping 300 mg daily dosing, taper to 150 mg once daily before complete discontinuation. 1

Clinical Decision Algorithm

1. Confirm diagnosis of MDD or SAD per DSM criteria 1
2. Screen for contraindications: seizure history, uncontrolled hypertension, MAOI use, eating disorders 1
3. Assess patient priorities: sexual function concerns, insomnia tolerance, comorbid smoking cessation needs 3
4. Initiate at 150 mg once daily in the morning 1
5. Increase to 300 mg after 4 days (MDD) or 7 days (SAD) 1
6. Monitor at 1-2 weeks for suicidality, agitation, and adverse effects 3
7. Reassess at 6-8 weeks: If inadequate response, modify treatment 3
8. Continue 4-9 months minimum after response; longer for recurrent depression 3