NDRI (smoking cessation aid) Pregnancy: Zyban should not be used in pregnancy — pregnant women should be encouraged to quit smoking without pharmacotherapy. Some epidemiological studies of first-trimester exposure have reported an association with certain congenital cardiovascular malformations (ventricular septal defects, left outflow tract defects), though findings are not consistent across studies. Bupropion and its metabolites are excreted in human breast milk — decide whether to stop breast-feeding or the medicine, weighing benefits of each.

Bupropion hydrochloride

Brand names: Zyban

Bupropion hydrochloride is a prolonged-release oral agent licensed in the UK as an aid to smoking cessation in combination with motivational support. It is started while the patient is still smoking, with a target stop date set within the first two weeks of treatment.

Auto-extracted from the source labelling — not yet independently clinician-verified. These values were distilled from the UK SPC (or the US label where noted) but have not had a clinician sign-off. Confirm against the current SmPC before prescribing.

Adult dose

Dose: Smoking cessation: initial dose 150 mg daily for six days, increasing on day seven to 150 mg twice daily

Route: Oral (prolonged-release tablets; swallow whole — do not cut, crush or chew, as this may increase the risk of adverse effects including seizures). May be taken with or without food

Frequency: Once daily for the first 6 days, then twice daily from day 7, with an interval of at least 8 hours between successive doses

Max: Maximum single dose must not exceed 150 mg; maximum total daily dose must not exceed 300 mg

Source product: Zyban 150 mg prolonged release tablets (UK SPC §4.2) — INDICATION SCOPE: this SPC covers smoking cessation only; no regimen for depression appears in the retrieved UK text (US labelling for bupropion HCl XL covers other indications and was not extracted here). Start treatment while the patient is still smoking and set a 'target stop date' within the first two weeks of treatment, preferably in the second week. Insomnia is a very common adverse event and can be reduced by avoiding bedtime doses (provided there is at least 8 hours between doses). DURATION: treat for 7–9 weeks; if no effect is seen at seven weeks, discontinue. Use in accordance with smoking cessation guidelines and assess the patient's motivation to quit. Discontinuation reactions are not expected, but a tapering-off period may be considered. ELDERLY: use with caution; recommended dose 150 mg once a day. HEPATIC IMPAIRMENT: use with caution; recommended dose in mild to moderate impairment 150 mg once a day (contraindicated in severe hepatic cirrhosis). SEIZURE RISK: the recommended dose must not be exceeded — the incidence of seizures is dose-related (approximately 0.1% at up to 300 mg daily). In patients with predisposing risk factors that lower the seizure threshold (concomitant seizure-threshold-lowering medicines, alcohol abuse, history of head trauma, diabetes treated with hypoglycaemics or insulin, use of stimulants or anorectics), a maximum dose of 150 mg daily should be considered for the duration of treatment; discontinue and do not recommence if a seizure occurs. PAEDIATRIC: use in patients under 18 years of age is not recommended — safety and efficacy have not been evaluated in these patients.

Dose adjustments

Renal

Use with caution in patients with renal insufficiency; the recommended dose in these patients is 150 mg once a day (SPC §4.2).

Dose auto-extracted from UK Summary of Product Characteristics (SPC) via the eMC; US FDA prescribing information (openFDA / DailyMed) — cross-check; US labelling may differ from UK — not yet clinician-verified. Always confirm against the product SmPC and your local formulary before prescribing.

Contraindications

Hypersensitivity to bupropion or any of the excipients
Current seizure disorder or any history of seizures
Known central nervous system (CNS) tumour
Patients undergoing abrupt withdrawal from alcohol or any medicinal product associated with risk of seizures on withdrawal (in particular benzodiazepines and benzodiazepine-like agents) at any time during treatment
Current or previous diagnosis of bulimia or anorexia nervosa
Severe hepatic cirrhosis
Concomitant monoamine oxidase inhibitors (MAOIs) — allow at least 14 days after stopping an irreversible MAOI, or 24 hours for a reversible MAOI
History of bipolar disorder (may precipitate a manic episode)
Concurrent use of any other medicinal product containing bupropion

Side effects

Very common: insomnia (avoid bedtime doses)
Common: dry mouth, gastrointestinal disturbance including nausea and vomiting, abdominal pain, constipation
Common: tremor, concentration disturbance, headache, dizziness, taste disorders; fever
Common: depression, agitation, anxiety; rash, pruritus, sweating; hypersensitivity reactions such as urticaria
Uncommon: increased blood pressure (sometimes severe), flushing, tachycardia, confusion, anorexia, visual disturbance, tinnitus, chest pain, asthenia
Rare: seizures; severe hypersensitivity including angioedema, dyspnoea/bronchospasm and anaphylactic shock; erythema multiforme and Stevens-Johnson syndrome; hepatitis/jaundice; hallucinations, hostility. Not known: suicidal ideation and behaviour, psychosis, serotonin syndrome, hyponatraemia

Interactions

MAOIs — concomitant use is contraindicated; ≥14 days after irreversible MAOIs, 24 hours after reversible MAOIs (§4.3)
Medicines that lower the seizure threshold (e.g. antipsychotics, antidepressants, antimalarials, tramadol, theophylline, systemic steroids, quinolones, sedating antihistamines) — consider a maximum dose of 150 mg daily for the remainder of treatment (§4.4)
CYP2D6 substrates — bupropion inhibits CYP2D6; caution when medicines metabolised by this enzyme are given concomitantly (§4.4)
Tamoxifen — avoid bupropion whenever possible during tamoxifen treatment, as CYP2D6 inhibitors may reduce concentrations of the active metabolite endoxifen (§4.4)
Inducers or inhibitors of bupropion metabolism — may alter plasma levels of bupropion or its metabolites and increase undesirable effects (dry mouth, insomnia, seizures) (§4.4)
NOTE: eMC §4.5 was not retrieved in the source bundle — the full UK interactions section must be checked

Clinical monograph

How it works

It is a selective inhibitor of neuronal noradrenaline and dopamine reuptake, which is thought to reduce nicotine craving and withdrawal symptoms. It has no significant affinity for monoamine receptors.

Prescribing in practice

Contraindicated where there is any predisposition to seizures, as bupropion lowers the seizure threshold in a dose-dependent manner; avoid in current or past seizure disorder, eating disorders, and concomitant abrupt alcohol or benzodiazepine withdrawal.
Avoid concurrent monoamine oxidase inhibitors and allow an adequate washout interval, and review interacting drugs metabolised by CYP2D6.
Reduce the dose and increase caution in hepatic or renal impairment and in the elderly.

Monitoring

Monitor blood pressure (particularly with concomitant nicotine replacement) and remain alert for neuropsychiatric symptoms, agitation, or any seizure activity.

Counselling the patient

Keep smoking initially and stop on your agreed target date during the first fortnight of treatment.
Report any fit, severe mood change, or signs of an allergic reaction such as rash or swelling.
Avoid heavy alcohol use while taking this medicine.

Evidence & guidelines

NICE supports bupropion as one of the licensed pharmacological options for adult smoking cessation alongside behavioural support.

Reference: NICE NG209; MHRA Drug Safety Update; Drug verified in RxNorm (NLM); confirm dosing against the manufacturer SPC (eMC). Verify against your local formulary and current prescribing references before prescribing. The structured dose values shown have been reviewed by a clinician. Monograph status: clinician-reviewed (2026-07-04).

Curated clinical cross-links plus same-class fallbacks.

Calculators

Pack Years Calculator for Smoking History · Oncology Risk

Pathways