FDA Information
Diphenhydramine was originally approved by the FDA in 1946.
Diphenhydramine is a first generation antihistamine drug. Despite being one of the oldest antihistamines on the market, it is by and large the most effective antihistamine available, either by prescription or over-the-counter, and has been shown to exceed the effectiveness of even the latest prescription drugs.
Please visit the official site of the FDA for further information.
Why is this medication prescribed?
Dosage and using this medicine
What special precautions should I follow?
What should I do if I forget a dose?
What side effects can this medication cause?