Print Print
CKS is no longer commissioned by the National Institute for Health and Clinical Excellence (NICE). NICE remains committed to providing a replacement service for CKS and is currently reviewing its options. In the meantime, although CKS content is now not being maintained, it still remains relevant and will continue to be made available. CKS content was generated under a programme of topic creation and update. To check if the topic you are viewing is current or out of date, please refer to the topic publication details by clicking on the 'How up-to-date is this topic?' link in the left hand menu on individual topic pages.

Smoking cessation - Management
What important adverse effects are associated with varenicline?

  • The most common adverse effect is nausea, which usually occurs early in the treatment period. Nausea is mild-to-moderate in severity and seldom results in discontinuation of treatment [ABPI Medicines Compendium, 2008].
  • Other common adverse effects include headache, insomnia, abnormal dreams, increased appetite, somnolence, dizziness, vomiting, constipation, diarrhoea, abdominal distension and discomfort, dyspepsia, flatulence, dry mouth, and fatigue [ABPI Medicines Compendium, 2008].
  • Post-marketing cases of myocardial infarction have been reported in people taking varenicline. No causal relationship has been established [ABPI Medicines Compendium, 2008].
  • Driving: varenicline may cause dizziness and somnolence, and therefore may influence the ability to drive and use machines. People are advised not to drive, operate complex machinery, or engage in other potentially hazardous activities until it is known whether varenicline affects their ability to perform these activities [ABPI Medicines Compendium, 2008].
  • Psychiatric illness: depression has been reported in people using varenicline who are trying to stop smoking, and symptoms of depression may include suicidal thoughts and behaviour [MHRA, 2008a]. Suicidal thoughts and behaviour have been reported in users of varenicline who have no known pre-existing psychiatric conditions, and while they continue to smoke.
    • A more recent nested cohort study which used the General Practice Research Database found no clear evidence that varenicline was associated with an increased risk of fatal or non-fatal self-harm [Gunnell et al, 2009]. However, a two-fold increased risk cannot be ruled out on the basis of the upper 95% confidence interval (CI) [MHRA, 2009a]. Compared with NRT:
      • The hazard ratio for self-harm in people prescribed varenicline was 1.12 (95% CI 0.67–1.88).
      • The hazard ratio for self-harm in people prescribed bupropion was 1.17 (95% CI 0.59–2.32).
      • The hazard ration for suicidal thoughts in people prescribed varenicline was 1.43 (95% CI 0.53–3.84).
      • There was no evidence that varenicline was associated with increased risk of depression (hazard ratio 0.88, 95% CI 0.77–1.00).
    • The MHRA has issued the following advice for healthcare professionals [MHRA, 2008b]:
      • Patients should be told to stop treatment and contact their doctor immediately if they develop suicidal thoughts or behaviour.
      • Varenicline should be stopped immediately if agitation, depressed mood, or changes in behaviour are observed that are of concern to the patient, family, or caregivers.
      • The safety and efficacy of varenicline in people with serious psychiatric illness have not been established. Patients who have a history of psychiatric illness should be monitored closely while taking varenicline.

© NHS Institute for Innovation and Improvement