Analgesics are medicines used to relieve pain such as headaches, backaches, joint pain, sore muscles, menstrual cramps, and pain that results from surgery, injury, or illness. While these drugs do not treat whatever is causing the pain, they can provide enough relief to make people more comfortable and to allow them to carry out their daily routines.

Among the most common analgesics are aspirin (acetylsalicylic acid), ibuprofen, naproxen sodium, and ketoprofen--all in the general category known as nonsteroidal anti-inflammatory drugs (NSAIDs). NSAIDs relieve pain and also reduce inflammation. Another common analgesic, acetaminophen (Tylenol, Panadol), provides pain relief but does not reduce inflammation. For some types of serious, chronic pain narcotic analgesics (also called opioid analgesics) are used. Analgesics in this category include natural narcotics (derived from the opium poppy), such as morphine and codeine (morphine-3-methyl ether), and synthetic narcotics, such as propoxyphene (Darvon) and meperidine (Demerol).

Salicylic...