Bupropion
Bupropion is an atypical antidepressant that inhibits norepinephrine and dopamine reuptake. It is used for major depression and smoking cessation, and is generally considered to have a favourable sexual side-effect profile compared with SSRIs.
- Chemical formula
- C13H18ClNO
- CAS number
- 34911-55-2
- ATC code
- N06AX12
- Molecular weight
- 239.74 g/mol
- Drug class
- Norepinephrine-dopamine reuptake inhibitor (NDRI) antidepressant
- Also known as
- Wellbutrin, Zyban, Amfebutamone
What is it?
Bupropion is a non-SSRI, non-tricyclic antidepressant in clinical use since 1985 in the US, marketed primarily as Wellbutrin (depression) and Zyban (smoking cessation). It is on the WHO Essential Medicines List and is widely available as authorised generic. The molecule is structurally and pharmacologically distinct from other antidepressant classes, which gives it a different side-effect profile and makes it a useful alternative when SSRIs are not tolerated.
Mechanism of action
Bupropion inhibits the reuptake of norepinephrine and dopamine, with much weaker effect on serotonin reuptake. The dopaminergic component distinguishes it from SSRIs and contributes to its activating profile and lower rate of sexual dysfunction. Its mechanism in smoking cessation is less fully understood but appears to involve nicotinic acetylcholine receptor antagonism in addition to monoamine effects.
Pharmacokinetics
Bupropion is rapidly absorbed after oral administration, with extensive hepatic metabolism via CYP2B6 to several active metabolites including hydroxybupropion. The parent compound has a half-life of around 14 hours, but active metabolites extend the effective half-life longer. Steady state is reached in about 8 days. Modified-release formulations (SR, XL) allow once or twice daily dosing.
Indications
Bupropion is approved for major depressive disorder, prevention of seasonal affective disorder recurrence, and smoking cessation. Off-label uses include adjunctive treatment of attention deficit hyperactivity disorder (ADHD) and antidepressant-induced sexual dysfunction. It is generally avoided in patients with seizure disorders, eating disorders, or recent benzodiazepine/alcohol withdrawal because of dose-related seizure risk.
Safety profile
Common adverse effects include dry mouth, insomnia, headache, agitation, nausea and weight loss. Sexual dysfunction is notably less common than with SSRIs. The most clinically important risk is seizures, which are dose-related and contraindicate bupropion in users with active seizure disorders. According to the prescribing information, bupropion should not be combined with MAOIs and requires a washout period when switching from or to MAOI therapy.
Products containing this ingredient
Frequently asked questions
How is bupropion different from SSRIs? ▾
Bupropion is an NDRI, not an SSRI — it primarily affects norepinephrine and dopamine rather than serotonin. Practical differences include lower sexual dysfunction rates, more activating profile, neutral or weight-loss effect rather than weight gain, and dose-related seizure risk. According to clinical guidelines, it is a reasonable first-line alternative to SSRIs for many patients.
Does bupropion help with smoking cessation? ▾
Yes — bupropion roughly doubles 6-month abstinence rates compared with placebo and is approved as Zyban for this indication. Treatment typically starts 1–2 weeks before the planned quit date and continues for 7–12 weeks. According to current smoking-cessation guidelines, it can be combined with nicotine replacement therapy for additional benefit.
Why does bupropion have a seizure risk? ▾
Bupropion lowers seizure threshold in a dose-dependent way. The risk is approximately 0.1% at standard doses and rises substantially at higher doses or in users with predisposing factors. According to the prescribing information, bupropion is contraindicated in seizure disorders, current or prior eating disorders, and acute alcohol or benzodiazepine withdrawal.
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