Whats the difference between diphenhydramine and dimenhydrinate? i know they are similar.

Both antihistamines: Diphenhydramine (also known as benadryl) is an antihistamine that is typically used to treat allergic reactions. It is somewhat sedating and causes drowsiness. Dimenhydrinate (dramamine) is also a histamine that is typically used to treat motion sickness. The body metabolizes dimenhydrinate into diphenhydramine, but this takes some time and leads to a slower onset of effect.

Diphenhydramine: Diphenhydramine is an antiallergy drug best known as benadryl (diphenhydramine). Dimenhydrinate is an over-the-counter drug used to prevent nausea and motion sickness. Dimenhydrinate is a combination of two drugs: Diphenhydramine and 8-chlorotheophylline, a chlorinated derivative of theophylline.