Synonyms Amfebutamone
Brand names Clorprax, Prexaton, Wellbutrin, Zyban
IUPAC name

IUPAC name






PDB fields




(Jmol 3D structure)
Mol. mass

239.741 g/mol

Bupropion is a noradrenaline-dopamine reuptake inhibitor,[note 1] nAChRs antagonist[note 2] and atypical antidepressant.[1] It is primarily used to treat nicotine dependence[note 3] under the brand names Prexaton, Zyban, although in some countries[note 4] it is also sold under the brand name, Wellbutrin, for the treatment of depression.[1][2] It can also be used in the treatment of another mood disorder called seasonal affective disorder.[3]

Side effectsEdit

Its major dose-limiting side effect[note 5] is seizures (although usually they are mild and not life-threatening) and consequently can be quite toxic in overdoses when compared to other antidepressants.[4] Despite this seizures are still uncommon with its use, except in overdose, of course, occurring in around 0.4% of patients treated with 450 mg/day or less of the drug.[5] Two other rare, yet potentially fatal, side effects of bupropion are allergic reactions like anaphylaxis and angioedema.[6] Other serious, yet uncommon/rare side effects include mania, suicidal thoughts or behaviour (that is, attempting/committing suicide), liver damage (even to the point of failure requiring a transplant), psychosis, aggression and Stevens-Johnson syndrome.[7]

Compared to other antidepressants it is associated with a lower risk of weight gain, mania,[note 6] drowsiness and sexual dysfunction.[note 7][8] Compared to other second-generation (newer) antidepressants it is associated with a relatively low rate of discontinuation (that is, people stopping the drug), although its efficacy (that is, its effectiveness) is unremarkable; it is worth noting, however, that the differences in effectiveness vary little from antidepressant to antidepressant, hence for patients this is probably meaningless.[9]

Its common side effects (occurring in over 1% of those treated with it) include:[7][10]

  • Dry mouth
  • Nausea
  • Vomiting
  • Constipation
  • Weight loss
  • Hives
  • Fever
  • Insomnia (reduced sleep/difficulty falling asleep)
  • Nightmares
  • Anxiety
  • Concentration difficulties
  • Dizziness
  • Agitation
  • Itching


Overdoses cause symptoms such as: hallucinations, nausea and vomiting, high heart rate, seizures (which occur in about a third of all overdose cases), coma and death.[11] Treatment usually consists of limiting absorption[note 8] if possible (like if the affected person gets medical attention within one hour of overdose).[1] Beyond this treatment is supportive (that is managing symptoms/complications as they arise), for example benzodiazepines (like diazepam [Valium]) may be used to control seizures.[1] Dialysis and diuresis (that is, putting one on a saline [salt water] drip so as to force the body to urinate it out faster) are likely useless, due to the low water solubility of bupropion and the high protein binding of it and its active metabolites.[1]


Bupropion inhibits the liver enzyme CYP2D6 (which is required for the metabolism of numerous drugs, including codeine, fluoxetine [Prozac] and tamoxifen) very potently, and depends on CYP2B6 for metabolism. CYP2B6 is induced (potentially reducing the effectiveness of bupropion) by certain antimicrobials (like efavirenz, rifampicin and ritonavir) and certain anti-seizure medicines (like phenobarbital and phenytoin). It is also inhibited (increasing the potential for seizures and other side effects) by certain blood thinners like clopidogrel and prasugrel.[12]


Structurally bupropion is chemically related to the amfetamines, although it possesses minimal potential for abuse or producing euphoria (that is, a high). Two salt forms are available for clinical use: the hydrobromide (HBr) and hydrochloride (HCl) salts.[1] Although, HCl salts are the only ones available in Australia.[13]

Bupropion has a half-life of 14 hours, hence necessitating three times daily dosing for immediate-release (IR) formulations (this means it releases the drug as rapidly as it can into the digestive tract upon ingestion). Sustained-release (SR) formulations (which release the drug relatively slowly) are the only formulations available in Australia and the U.K.; they have a half-life of 20 hours (brand names: Clorprax, Prexaton, Zyban); and need to be dosed twice daily. Extended release (XR) formulations (which release the drug even more gradually, facilitating once daily dosing) can be taken once daily and are usually called by the brand name Wellbutrin XL but are only available in countries where bupropion is marketed to treat depression.[7]

It is about 84% plasma protein bound and is principally metabolized by CYP2B6 to the following active metabolites: hydroxybupropion (in animal studies it was purported to be half as active as bupropion), threohydrobupropion (one-fifth as active in animal studies) and erythrohydrobupropion (also one-fifth as active in animal studies).[1][10]


Bupropion racemate
300px (R)-bupropion
300px (S)-bupropion

External linksEdit


  1. See this for explanatory notes on what this means
  2. That is, it blocks the receptors that mediate the pleasurable effects of nicotine
  3. That is, to help people quit smoking
  4. For example the USA, Canada, Hong Kong and Singapore
  5. This means this side effect is more frequent at higher doses than at lower doses. In fact it was initially withdrawn from the U.S. market soon after it was introduced around 1985 due to this side effect. It was later re-introduced with restrictions on its maximum dosage to be used clinically.
  6. A dangerously high mood, usually associated with bipolar disorder.
  7. As you can probably guess this is an umbrella term referring to impotence, that is, difficulty achieving an erection in guys, difficulty achieving an orgasm, reduced libido, etc.
  8. Via activated charcoal and stomach pumps

Reference listEdit

  1. 1.0 1.1 1.2 1.3 1.4 1.5 1.6 Brayfield, A, ed. (22 October 2013). "Bupropion". Martindale: The Complete Drug Reference. London, UK: Pharmaceutical Press. Retrieved 28 July 2014.
  2. Saiz Ruiz, J; Gibert, J; Gutiérrez Fraile, M; Bobes, J; Vallejo, J; Iglesias, C; Iriarte, V (2011). "Bupropion: efficacy and safety in the treatment of depression." (PDF). Actas Espanolas de Psiquiatria. 39 Suppl 1: 1–25. PMID 22983817.
  3. Niemegeers, P; Dumont, GJ; Patteet, L; Neels, H; Sabbe, BG (September 2013). "Bupropion for the treatment of seasonal affective disorder.". Expert Opinion on Drug Metabolism & Toxicology 9 (9): 1229–40. PMID 23705752. doi:10.1517/17425255.2013.804062. 
  4. Hawton, K; Bergen, H; Simkin, S; Cooper, J; Waters, K; Gunnell, D; Kapur, N (May 2010). "Toxicity of antidepressants: rates of suicide relative to prescribing and non-fatal overdose.". The British Journal of Psychiatry 196 (5): 354–8. doi:10.1192/bjp.bp.109.070219. PMC 2862059. PMID 20435959.
  5. Saiz Ruiz, J; Gibert, J; Gutiérrez Fraile, M; Bobes, J; Vallejo, J; Iglesias, C; Iriarte, V (2011). "Bupropion: efficacy and safety in the treatment of depression." (PDF). Actas Espanolas de Psiquiatria. 39 Suppl 1: 1–25. PMID 22983817. 
  6. Joint Formulary Committee (2013). British National Formulary (BNF) 65 (65 ed.). London, UK: Pharmaceutical Press. p. 324. ISBN 978-0-85-711084-8. 
  7. 7.0 7.1 7.2 Rossi, S, ed. (July 2014). "Bupropion". Australian Medicines Handbook. Adelaide, Australia: Australian Medicines Handbook Pty Ltd. Retrieved 7 September 2014. 
  8. Moreira, R (October 2011). "The efficacy and tolerability of bupropion in the treatment of major depressive disorder.". Clinical Drug Investigation. 31 Suppl 1: 5–17. PMID 22015858. doi:10.2165/1159616-S0-000000000-00000. 
  9. Cipriani, A; Furukawa, TA; Salanti, G; Geddes, JR; Higgins, JP; Churchill, R; Watanabe, N; Nakagawa, A; Omori, IM; McGuire, H; Tansella, M; Barbui, C (February 2009). "Comparative efficacy and acceptability of 12 new-generation antidepressants: a multiple-treatments meta-analysis." (PDF). Lancet 373 (9665): 746–58. PMID 19185342. doi:10.1016/S0140-6736(09)60046-5. 
  10. 10.0 10.1 "PRODUCT INFORMATION CLORPRAX® SUSTAINED RELEASE TABLETS" (PDF). TGA eBusiness Services. Pyrmont, Australia: Sandoz Pty Ltd. 15 June 2009. Retrieved 3 September 2014. 
  11. Taylor, D; Paton, C; Shitij, K (2012). Maudsley Prescribing Guidelines in Psychiatry (11th ed.). West Sussex: Wiley-Blackwell. ISBN 978-0-47-097948-8.
  12. Rossi, S, ed. (July 2014). "Drugs and CYP Enzymes". Australian Medicines Handbook. Adelaide, Australia: Australian Medicines Handbook Pty Ltd. Retrieved 7 September 2014. 
  13. "Product and Consumer Medicine Information". TGA eBusiness Services. Canberra, Australia: Therapeutic Goods Administration. 1 December 2014. Retrieved 1 December 2014.