What to do if benadryl (diphenhydramine) raises blood pressure?

Try alternative: Check labels, you can try Meclizine (bonine) or dimenhydrinate (dramamine) instead of Benadryl (diphenhydramine). Other brand names for the two alternative meds, so you will have to check. Or can try a nonsedating antihistamine (zyrtec / allegra). All of these "might" increase your bp, so have to try and see. May have to switch to nasal spray (/afrin, etc.) if appropriate for your symptoms.