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α4β2 nicotinic partial agonist

Varenicline

Brand names: Champix

Varenicline is an oral nicotinic-receptor partial agonist used as an aid to smoking cessation. It reduces cravings and lessens the reward and satisfaction obtained from smoking.

Dosing — being independently re-sourced

ClinCalc Pro is rebuilding its dose data from primary open sources — the manufacturer SmPC (eMC), the WHO Model Formulary and other official references — under clinician review. This drug's structured dose is not yet published here. Confirm all doses against the product SmPC and your local formulary before prescribing.

US labelling (FDA)

Reference — US labelling, may differ from UK

Begin varenicline tablets dosing one week before the date set by the patient to stop smoking. Alternatively, the patient can begin varenicline tablets dosing and then quit smoking between days 8 and 35 of treatment. ( 2.1 ) Starting Week: 0.5 mg once daily on days 1 to 3 and 0.5 mg twice daily on days 4 to 7. ( 2.1 ) Continuing Weeks: 1 mg twice daily for a total of 12 weeks. ( 2.1 ) An additional 12 weeks of treatment is recommended for successful quitters to increase likelihood of long-term abstinence. ( 2.1 ) Consider a gradual approach to quitting smoking with varenicline tablets for patients who are sure that they are not able or willing to quit abruptly. Patients should begin …

Source: US FDA prescribing information (openFDA / DailyMed), label dated 2025-05-08. Accessed 2026-06-12. US dosing and indications can differ from UK practice — use UK sources for prescribing decisions.

Clinical monograph

How it works

It binds partially to alpha-4-beta-2 nicotinic acetylcholine receptors, providing enough stimulation to relieve withdrawal while blocking nicotine from those receptors, so smoking becomes less rewarding.

Prescribing in practice

  • Monitor mood and behaviour, and advise the person to report low mood, agitation, unusual behaviour or suicidal thoughts.
  • Treatment is started before the planned quit date, with the dose titrated up over the first week.
  • Nausea is common, along with abnormal or vivid dreams, insomnia, headache and constipation; dose reduction may help if side effects are troublesome.

Monitoring

Monitor mood, behaviour and smoking status during treatment, with particular attention to any new or worsening psychiatric symptoms.

Counselling the patient

  • Start the medicine before your quit date and set a date to stop smoking as advised.
  • Take it after food with a full glass of water to reduce nausea.
  • Tell someone and seek advice promptly if you notice low mood, agitation or thoughts of self-harm.

Evidence & guidelines

Recommended for smoking cessation by NICE (NG209).

Reference: NICE NG209; MHRA; Drug verified in RxNorm (NLM); confirm dosing against the manufacturer SPC (eMC). Verify against your local formulary and current prescribing references before prescribing. Monograph status: clinician-reviewed (2026-07-04).

Related

Curated clinical cross-links plus same-class fallbacks.

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