The inadequacy of pain treatment has been demonstrated in many patient groups suffering from acute pain. The injectable nonsteroidal anti-inflammatory drugs (NSAIDs), including indomethacin, diclofenac, ketoprofen and ketorolac, provide relief from the pain associated with several different conditions. When administered alone or in combination with low doses of opioids, NSAIDs provide good pain relief after musculoskeletal trauma or operation. The main advantage of these agents is that they may form the first-line therapy for pain relief and thus decrease the need of opioids. This avoids respiratory depression which can be associated with opioids. In contrast to opioids, NSAIDs do not cause respiratory depression or have marked adverse effects on the central nervous system. However, they may be associated with adverse effects of the gastrointestinal tract, liver and kidneys, and may increase pre- and postoperative bleeding and cause allergic reactions. These effects are related to the ability of NSAIDs to inhibit prostaglandin synthesis. Use of NSAIDs has to be considered carefully in patients with asthma, allergy to aspirin and NSAIDs, atopy, peptic ulcer or bleeding disorders (such as abnormalities in blood coagulation or coagulation deficits). These considerations are especially important in elderly patients. Having taken these contraindications into account, many clinical studies have demonstrated that NSAIDs are at least as safe as opioids when administered in the short term. However, few studies have specifically monitored adverse effects or included patients over 65 to 70 years of age. In addition, patients with risk factors have often been excluded from the trials. Therefore, the risk-benefit ratio of NSAIDs requires further assessment.