Apap is aceteminophen (sp?) commonly known as the brand name Tylenol. Apap is simply a way of abreviating the generic chemical name. Apap is an over the counter pain reliever/fever reducer (Tylenol). However, it is commonly combined with prescription narcotics, in varying dosages, to form combo pain relievers. Common examples are Vicodin, Lorcet (apap& hydrocodone) Percocet, Endocet, Roxicet (oxycodone& apap) and ultracet (tramadol& apap).