ABSTRACT

Acetaminophen (paracetamol), others is the active metabolite of phenacetin, a so- called coal tar analgesic. It is among the Paraaminophenol derivatives. Here, acetanilide is the parent member of this group of derivates; acetanilide was introduced into medicine under the name of antifebrin (Cabn and Hepp, 1986) who had accidentally discovered its antipyretic action. However, acetanilide proved to be excessively toxic and in the search of less toxic compounds, Paraaminophenol was tried in the belief that the body oxidizes acetanilide to this compound. Toxicity was not licensed, however, a number of chemical derivatives of Para —aminophenol was then tested. Acetaminophen was first used in medicine (Von Mering, 1963) however; it has gained popularity only since 1949 after it was recognized as the major active metabolite of both acetanilide and phenacetin. As earlier said acetaminophen is the active metabolite of phenacetin, a so-called coal tar analgesic. It is an effective alternative of aspirin as an analgesic- antipyretic agent. This is because unlike aspirin, its anti-inflammatory activity is weak and therefore it is not a useful agent to treat inflammatory conditions.