Drug Interactions With Varenicline
Varenicline tartrate (Chantix™) is unlikely to interact with most other medicines. It has been studied in combination with many other medications without causing any problems.
Cimetidine (Tagamet®) can increase the level of varenicline in your blood, possibly increasing your risk for side effects of varenicline. However, this interaction usually does not cause any problems for most people. If you notice an increase in side effects when taking cimetidine, you may want to discuss this with your healthcare provider (who may suggest using one of the many cimetidine alternatives available.)
It is possible that not all drug interactions with varenicline are known at this time. Therefore, you should talk with your pharmacist or healthcare provider about any specific drug interactions that may apply to you.