A rationale for combining acetaminophen and NSAIDs for mild-to-moderate pain.

Analgesic therapy that combines individual agents with different mechanisms of action has potential advantages for the management of mild-to-moderate pain in the outpatient setting. Theoretically, this approach can lead to greater efficacy and fewer adverse events. While the precise mechanism of action for the analgesic effect of acetaminophen remains uncertain, accumulating evidence suggests that its activity resides primarily in the central nervous system. In contrast, the site of action for the analgesic effect of nonsteroidal anti-inflammatory drugs (NSAIDs) is predominantly peripheral, within injured or inflamed tissue. Several controlled clinical studies among patients with musculoskeletal conditions, dental pain, or postoperative pain have shown that combinations of acetaminophen and NSAIDs provide additive pain-relieving activity, thereby leading to dose-sparing effects and improved safety. Further studies are warranted to determine the clinical utility and safety of acetaminophen/NSAID combinations as analgesic therapy for common conditions associated with mild-to-moderate pain.