Champix (also called varenicline) is not currently available in the UK or Europe. It has been withdrawn as a precaution, because of an impurity found in the medicine.
It may be unavailable long-term. It's not yet known whether it will be available again in future.
Champix is a medicine that can help you stop smoking. It was only available on prescription. It reduces the cravings for nicotine and helps with the withdrawal symptoms you get when you stop smoking. These can include an urge to smoke again, feeling depressed or irritable, and difficulty sleeping.