Sounds like 'var-eh-nik-lin'

Easy-to-read medicine information about varenicline – what it is, how to take varenicline safely and possible side effects.

Type of medicine Also called
  • Medicine to stop smoking   
  • Champix ®

 What is varenicline?

  • Varenicline is a medicine to help adults stop smoking.
  • It works by blocking the effects of nicotine in the brain.
  • It can help to reduce craving and withdrawal symptoms that happen while you give up smoking.
  • Varenicline is available from your pharmacy only on a prescription.
  • Read more about how to quit smoking.


  • Take varenicline exactly as your doctor has told you.
  • The following is a guide:
    • Varenicline is usually taken over a period of  12 weeks.
    • Start varenicline 1 week before your target quit date. This helps build up the medicine in your body while you are able to smoke for a few more days.
    • When you first start taking varenicline, the dose is slowly increased to lessen the chance of side effects such as nausea, and unusual dreams.
    • During this first week, it is okay to smoke. Take one 0.5-milligram tablet once a day for 3 days, then increase to one 0.5-milligram tablet twice a day for 4 days.
    • Stop smoking on the quit date and begin taking 1 milligram twice a day for the rest of the 12-week treatment period.

 How to take varenicline

  • Swallow the tablets whole with a full glass of water.
  • Take varenicline with food. This helps to prevent stomach upset.
  • Limit drinking alcohol while you are taking varenicline. Drinking alcohol while taking varenicline may increase the risk for mood changes. 
  • If you forget to take your tablet, take it as soon as you remember that day.
  • But, if it is nearly time for your next tablet, just take the next tablet at the right time. Do not take double the amount of tablets.

Possible side effects

Like all medicines, varenicline can cause unwanted side effects, although not everyone gets them. Often unwanted side effects improve as your body adjusts to the new medicine

Side effects What should I do?
  • Indigestion
  • Feeling sick (nausea)
  • Stomach discomfort
  • These are quite common when you first start taking varenicline.
  • Try taking varenicline with food.
  • Drowsiness
  • Tiredness
  • Weakness
  • These are quite common when you first start taking varenicline.
  • Be careful when driving or using tools until you know how this medicine affects you.
  • Limit alcohol intake.
  • Tell your doctor if troublesome.
  • Difficulty sleeping
  • Sleep disturbances
  • Abnormal dreams
  • Tell your doctor if troublesome.
  • Agitation
  • Feeling anxious
  • Mood changes
  • Depression
  •  Tell your doctor immediately or ring HealthLine


Varenicline  may interact with a number of important medications and herbal supplements so check with your doctor or pharmacist.

Learn more

Medsafe Consumer Information Sheet Champix
New Zealand Formulary Patient Information Varenicline 
For more information on how to quit smoking, see the Quitline website

Credits: Sandra Ponen, Pharmacist. Reviewed By: Dr Janine Bycroft, GP, Health Navigator NZ