Prescription Medication — Information Only

Varenicline

A prescription medication that reduces both craving and the rewarding effect of nicotine. Among the most effective single medications.

What it is

Varenicline is a prescription medicine (sold under brand names such as Chantix in some markets) that partially stimulates nicotine receptors in the brain.

How it works

It binds to nicotinic receptors, reducing withdrawal symptoms and blocking much of the pleasure from smoking if a person does smoke, which weakens the reward loop.

Evidence and effectiveness

Cochrane reviews and network meta-analyses rank varenicline among the most effective single medications for quitting, roughly doubling or more the odds of success versus placebo in clinical trials.

Evidence strength: Strong

Guidelines: Recommended by WHO (2024), USPSTF (2021) and NICE NG209 (UK) as a first-line medication for adult smokers.

Compared with other options: Network meta-analyses place varenicline among the most effective single medications, ahead of single-form NRT and bupropion; combination NRT is roughly comparable. Cytisine was non-inferior in one randomized comparison, with fewer reported adverse events.

Common adverse effects

Nausea is the most commonly reported side effect (about 3 in 10 users in clinical trials), usually mild and early in treatment. Abnormal dreams and insomnia are also common. Less common reports include headache and constipation.

Important safety considerations

The EAGLES trial (2016, 8,144 participants with and without psychiatric disorders) found no significant increase in moderate-to-severe neuropsychiatric adverse events compared with placebo or nicotine patch; regulators subsequently removed the boxed warning. Mood or behavior changes should still be reported to the prescriber promptly. Kidney function and medical history affect suitability.

Reported community experiences

Community reports describe reduced enjoyment of cigarettes and reduced craving, alongside reports of nausea, unusual dreams and mood changes. Community records are being compiled in the Experience Database.

Common considerations

  • It requires a prescription: discuss suitability, dosing and side effects with a healthcare professional
  • Report any significant mood changes to the prescriber promptly
  • Combine with behavioral support for best results

Limitations

This is a prescription medication. This page provides information only; it cannot determine whether varenicline is appropriate for any individual. Contraindications and warnings must be discussed with a prescribing professional.

Questions to ask a healthcare professional

  • Is this medication appropriate for my medical history and current conditions?
  • What dose and duration would you recommend for me, and how should I take it?
  • What side effects should I expect and which ones mean I should contact you?
  • Does it interact with any of my other medications?
  • What happens if I smoke while using it?
  • How long should I continue it after quitting?

This page is information only. It does not recommend this medication for any individual, does not suggest doses, and does not replace professional medical advice.

Source: Cochrane reviews and network meta-analyses rank varenicline among the most effective single medications for quitting, roughly doubling or more the odds of success versus placebo in clinical trials. R-002 (Cochrane partial-agonist review); EAGLES trial (Anthenelli 2016); R-013 (WHO 2024 guideline); R-012 (NICE NG209). Community reports are de-identified and are not scientific evidence. Last reviewed: October 2026.