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Varenicline

What it is

A prescription medication (marketed as Chantix/Champix) developed specifically for smoking cessation. It is a partial agonist at nicotinic acetylcholine receptors.

How it works

It binds to the same brain receptors as nicotine. It partially stimulates them — reducing withdrawal and craving — while blocking nicotine from fully activating them, which reduces the reward of smoking.

What the evidence shows

  • Cochrane's review of nicotine receptor partial agonists found varenicline increases quit rates substantially versus placebo (roughly 2–3x) — see R-002.
  • The EAGLES trial (8,144 participants, with and without psychiatric disorders) found no significant increase in moderate-to-severe neuropsychiatric adverse events versus placebo or patch, and varenicline was the most effective of the compared treatments — see R-015.
  • The 2016 network meta-analysis overview placed varenicline among the most effective single medications — see R-008.
  • WHO (2024), USPSTF (2021) and NICE (NG209) all recommend varenicline.

Common considerations

  • Nausea is the most commonly reported side effect, usually mild and early in treatment.
  • Abnormal dreams and insomnia are also commonly reported.
  • Following the EAGLES results, regulators removed the black-box neuropsychiatric warning. People with a history of psychiatric illness were included in the trial; individual assessment still matters.
  • Availability varies by country and by supply history; generic forms exist in several markets.

Questions to ask a healthcare professional

  • Is varenicline suitable given my medical history and current medications?
  • What should I expect in the first weeks, and what side effects should I report?
  • How does it compare with NRT or cytisine for me specifically?

Related: NRT · Bupropion · EAGLES record