Can I take Benadryl when on propranolol?

There are moderate interactions between the two. Personally when taking both I did get extremely fatigued/sleepy. It was manageable as I was taking the Benadryl at night so I wasn’t sniffling while trying to sleep. I could not take them both in the morning and function normally. We are all different, but I hope this helps.

Hello,

Drug Interaction Report
5 potential interactions and/or warnings found for the following 2 drugs:

Benadryl (diphenhydramine)
propranolol

Interactions between your drugs
Moderate
propranolol diphenhydrAMINE
Applies to: propranolol, Benadryl (diphenhydramine)

Propranolol and diphenhydrAMINE may have additive effects in lowering your blood pressure. You may experience headache, dizziness, lightheadedness, fainting, and/or changes in pulse or heart rate. These side effects are most likely to be seen at the beginning of treatment, following a dose increase, or when treatment is restarted after an interruption. Let your doctor know if you develop these symptoms and they do not go away after a few days or they become troublesome. Avoid driving or operating hazardous machinery until you know how the medications affect you, and use caution when getting up from a sitting or lying position. 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.

Moderate Moderately clinically significant. Usually avoid combinations; use it only under special circumstances.

The other 4 interactions are Drug and food interactions.

Source and more info: https://www.drugs.com/interactions-check.php?drug_list=896-1617,1956-0

Regards, masso