Analgesic:

A drug that is used primarily to relieve pain. Analgesics are of three basic types: (1) Simple, nonnarcotic analgesics that relieve pain by suppressing the local production of prostaglandins and related substances; examples are acetaminophen, aspirin and the large group of nonsteroidal anti-inflammatory drugs known as aspirin substitutes (Motrin, Advil, Naprosyn, etc.). (2) Narcotic analgesics or opioids ("like opium" derivatives) that relieve pain by surpressing its perception in the brian; examples are morphine, codeine and hydrocodone (natural derivatives of opium), and meperidine or pentazocine (synthetic drug products). (3) Local anesthetics that prevent or relieve pain by rendering sensory nerve endings insensitive to painful stimulation; an example is the urinary tract analgesic phenazzopyridine (Pyridium).

--From The Essential Guide to Prescription Drugs