Wellbutrin Tapering Guide
bupropion
Boxed Warning
Suicidality risk in children, adolescents, and young adults under 25 during initial treatment.
Overview
Bupropion is a norepinephrine-dopamine reuptake inhibitor (NDRI) approved for major depressive disorder, seasonal affective disorder, and smoking cessation (as Zyban). It is unique among antidepressants for its activating profile and lack of sexual side effects or weight gain.
75mg, 100mg, 150mg, 300mg
Immediate-release tablets: 75mg, 100mg; Sustained-release tablets (SR): 100mg, 150mg, 200mg; Extended-release tablets (XL): 150mg, 300mg
Category C (risk cannot be ruled out)
Mechanism of Action
Inhibits reuptake of norepinephrine and dopamine (NDRI). Does not significantly affect serotonin reuptake. The active metabolites hydroxybupropion, threohydrobupropion, and erythrohydrobupropion also contribute to pharmacological activity.
Taper Notes
Discontinuation profile is markedly milder than SSRIs/SNRIs — no serotonergic rebound and minimal classical withdrawal. IR tablets permit splitting for graduated reductions. Watch for re-emergence of underlying depression in the weeks following discontinuation.
Maudsley Deprescribing Guidance
Standard stepwise reductions are usually sufficient given the absence of classical antidepressant discontinuation syndrome. IR formulation provides the most flexibility; do not split SR or XL formulations (matrix integrity affects seizure risk).
Tapering Protocol
Evidence-based phased reduction schedule. Always taper under medical supervision.
| Phase | Duration | Notes |
|---|---|---|
| Initial reductions | 2-4 weeks | Reduce by ~25% using available XL strengths (300 mg → 150 mg). Most patients tolerate initial steps without significant rebound. |
| Formulation switch | 2-4 weeks | Convert to SR or IR formulation for greater dose-step granularity. Verify total daily dose equivalence during the switch. |
| Final reductions | 4-6 weeks | IR tablets (75/100 mg) permit the smallest increments. Discontinuation syndrome is typically mild compared to SSRIs/SNRIs. |
Withdrawal Timeline
1-3 days after dose reduction
3-7 days
1-2 weeks for most symptoms
Fatigue and motivational deficits may linger 2-4 weeks. No serotonin-related symptoms (no brain zaps). Wellbutrin has one of the mildest withdrawal profiles among antidepressants.
Clinical Pearls
Practical considerations for clinicians supervising Wellbutrin tapers.
- 1Bupropion discontinuation is mechanistically distinct from SSRI withdrawal — no brain zaps, no serotonergic rebound. Predominant features are fatigue, anergia, and mild dysphoria reflecting catecholaminergic withdrawal.
- 2IR formulation (75/100 mg) provides the finest dose-step granularity and is preferred for the terminal phase of the taper.
- 3XL and SR formulations must not be split or crushed — disrupting the matrix produces immediate-release kinetics with increased seizure risk.
- 4Patients commonly report appetite increase and modest weight gain post-discontinuation; counsel that this typically normalizes within several weeks.
Common Withdrawal Symptoms
Interactions & Safety
Drug Interactions
- MAOIs — contraindicated (hypertensive crisis)
- Potent CYP2D6 inhibitor; increases levels of TCAs, SSRIs (paroxetine, fluoxetine levels affected less), metoprolol, flecainide, and other CYP2D6 substrates
- CYP2B6 inhibitors (ticlopidine, clopidogrel) increase bupropion levels
Food Interactions
- Food does not significantly affect SR/XL absorption
- Avoid alcohol (lowers seizure threshold)
Contraindications
- Seizure disorder
- Current or prior bulimia or anorexia nervosa (increased seizure risk)
- MAOIs within 14 days
Toxicity
Dose-dependent seizure risk (contraindicated above 450mg/day). Hypertension. Lower toxicity in overdose than TCAs but seizures and cardiac conduction delays possible.
Pharmacokinetics
ADME Profile
Well absorbed after oral administration. Tmax ~2 hours (IR), ~3 hours (SR), ~5 hours (XL). Extensive first-pass metabolism; bioavailability ~5–20%. Food does not significantly affect absorption of SR/XL formulations.
~20 L/kg (estimated)
Extensively metabolized hepatically via CYP2B6 (primary) to the active metabolite hydroxybupropion. Non-CYP pathways produce threohydrobupropion and erythrohydrobupropion.
Renal (~87%, with <1% as unchanged bupropion) and fecal (~10%).
~84%
~200 L/hr (apparent oral clearance)
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