Impact of non-narcotic oral analgesics on pain management.

Of the four categories of oral analgesics, three have been available since the 19th century. Although adequate doses of the more potent oral opioids such as morphine and methadone are effective even in severe pain, the commonly used "weak" narcotics such as codeine and propoxyphene are no more effective than usual doses of aspirin or acetaminophen. Furthermore, the opioids produce gastrointestinal and central nervous system adverse effects, and, during long-term administration, tolerance may develop and there is a risk of drug dependence. Aspirin and acetaminophen are the traditional agents of choice for oral analgesic therapy; until 10 years ago, there were no single-entity, oral analgesics--with the exception of large doses of oral narcotics--that were more effective than usual doses of aspirin or acetaminophen. However, there is a ceiling on the analgesic effect attainable with safe doses of these drugs, which may in part be overcome through the use of the third category of oral analgesics, combinations of aspirin or acetaminophen with oral opioids. The fourth category of oral analgesics constitutes the most important recent development in pain management with analgesic drugs: the newer peripherally acting, nonsteroidal anti-inflammatory analgesics, some of which are clearly more efficacious than aspirin or acetaminophen and compare favorably not only with full doses of narcotic combination products but even, in some cases, with strong injectable opioids. On repeated dosing, some nonsteroidal anti-inflammatory drugs are better tolerated than aspirin and some have a much longer duration of analgesic effect than aspirin or acetaminophen. Further study is needed to compare nonsteroidal anti-inflammatory drugs among themselves and to determine their value in chronic pain and in combination therapy.