Tylenol PM
Tylenol PM is the trademark for a mixture of paracetamol (acetaminophen) and diphenhydramine, distributed by Johnson & Johnson. It is marketed as a combined analgesic and sedative, or more simply, pain reliever and sleep aid, intended to treat occasional headaches and minor aches and pains with accompanying sleeplessness. It is listed as non-habit forming.
Acetaminophen alone is sold as simply Tylenol, while diphenhydramine alone is marketed as Simply Sleep, and as Benadryl.
Diphenhydramine is an anti-histamine and is also the active ingredient in Benadryl(allergies) and Benylin which is used in cough and cold therapy as an anti-cough (anti-tussive) with the drying effect of the anti-histamine. The drowsiness is caused by the anti-histamine.