Varenicline (Champix®)

Sounds like 'var-eh-nik-line'

Varenicline is used to help you stop smoking. Varenicline is also called Champix.

Notification January 2022

Varenicline is not currently available in Aotearoa New Zealand due to a supply problem. It's not known when it will be available again. Talk to your doctor about other options for stopping smoking. Learn more: Varenicline (Champix): Supply issue

What is varenicline?

Varenicline is a medicine used to help you stop smoking. It's usually used when nicotine replacement therapy (NRT) or other medicines have not been effective.

Varenicline works by blocking the effects of nicotine in the brain. Varenicline can help to reduce craving and withdrawal symptoms that happen while you give up smoking. Varenicline doesn't contain nicotine and it's not addictive. Read more about how to stop smoking. 

What are the benefits of varenicline?

Taking varenicline increases your chances of quitting smoking. It approximately doubles to triples the chances of giving up smoking long-term. It doesn't contain nicotine, which is important to some people.


In Aotearoa New Zealand varenicline is available as 0.5 mg and 1 mg tablets.  

  • You'll be started off on a low dose which will be increased slowly. This decreases the chance of you developing side effects such as nausea, and unusual dreams.
  • Varenicline is usually started 1 to 2 weeks before your target quit date (the target quit date is the day you want to stop smoking).
  • The total course is usually 12 weeks.
During the first week
  • Take 0.5 mg once a day for 3 days.
  • Then increase to 0.5 mg twice a day for 4 days.
  • It is okay to smoke during this time. 
After the first week:
  • Stop smoking on the quit date then take 1 mg twice a day for the rest of the 12 weeks.
  • If you cannot tolerate this dose, your doctor may advise you to lower this to 0.5 mg twice a day.

How to take varenicline

  • Timing:
    • If you're taking the tablets once a day, take your tablet either in the morning or the evening.
    • If you're taking your tablets twice a day, take 1 tablet in the morning and 1 tablet in the evening.
  • Taking: Swallow the tablets whole with a glass of water. You can take them with or without food.
  • Avoid alcohol: Limit alcohol intake while you're taking varenicline. Drinking alcohol while taking varenicline may increase the risk for mood changes, dizziness and drowsiness. 
  • Missed dose: 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 number of tablets.

Things to consider while you are taking varenicline

Varenicline can interact with some medicines, herbal supplements and rongoā Māori, so check with your doctor or pharmacist before starting varenicline and before starting any new products.

Possible side effects

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

Side effects What should I do?
  • Indigestion
  • Feeling sick (nausea) or vomiting (being sick)
  • Stomach discomfort
  • Constipation
  • Gas (passing wind)
  • Dry mouth, changes in taste
  • These are quite common when you first start taking varenicline.
  • Try taking varenicline with food.
  • Headache
  • 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 these side effects bother you.
  • Difficulty sleeping
  • Strange dreams
  • These are quite common when you first start taking varenicline.
  • Tell your doctor if they bother you.
  • Changes in behaviours or thinking
  • Mood swings
  • Feeling anxious
  • Depression (new or worsening)
  • Thoughts of suicide
  • These are rare but serious side effects.
  • Tell your doctor immediately or ring Healthline 0800 611 116.
  • Signs of an allergic reaction such as a skin rash or difficulty breathing
  • Allergic reactions are rare but serious.
  • Stop taking varenicline.
  • Tell your doctor immediately or phone Healthline free on 0800 611 116.
For more information on side effects, see the Medsafe consumer information leaflets Varenicline Pfizer.

Did you know that you can report a medicine side effect to the Centre for Adverse Reactions Monitoring (CARM)? Report a side effect to a product.

Learn more


Useful resources for healthcare professionals

Credits: Sandra Ponen, Pharmacist. Reviewed By: Angela Lambie, Pharmacist, Auckland Last reviewed: 07 Feb 2023