Drug Interactions between Benadryl and varenicline

Varenicline may alter the way you react to alcohol. Some patients treated with varenicline have experienced decreased tolerance to alcohol, including increased drunkenness, unusual or aggressive behavior, or they had no memory of things that happened. You should limit the consumption of alcohol until you know whether varenicline affects your tolerance for alcohol. Also use caution driving or operating machinery until you know how quitting smoking and/or varenicline may affect you. If you develop nervousness, agitation, hostility, aggressive behavior, depression, thoughts of suicide, or have other changes in your behavior or thinking that are
not typical for you, you should immediately stop taking varenicline and contact your doctor. It is important to tell your doctor about all other medications you use, including vitamins and herbs. Do not stop using any medications without first talking to your doctor.

Ask your doctor before using diphenhydrAMINE together with ethanol (alcohol). Use alcohol cautiously. Alcohol may increase drowsiness and dizziness while you are taking diphenhydrAMINE. You should be warned not to exceed recommended dosages and to avoid activities requiring mental alertness. If your doctor prescribes these medications together, you may need a dose adjustment to safely take this combination. It is important to tell your doctor about all other medications you use, including vitamins and herbs. Do not stop using any medications without first talking to your doctor.