NON-STEROIDAL ANTI-INFLAMATORY DRUGS (NSAIDS) AND ACETAMINOPHEN IN THE TREATMENT OF AN ACUTE MUSCLE INJURY

Abstract

Muscle injuries are common in athletes. Non-steroidal anti-inflammatory drugs (NSAIDs) are frequently used to treat them. It is not known whether the anti-inflammatory effects of these drugs are important or whether their effectiveness is a result of their central analgesic effect. PURPOSE: evaluate and compare the effects of non-steroidal anti-inflammatory medication (NSAID), an analgesic (acetaminophen) and placebo in an experimental, acute muscle contusion model. METHODS: A standardized, unilateral, non-penetrating injury was created to the tibialis anterior muscle of 96 adult, male mice. Four treatment groups were used: Group 1 placebo treatment, Group 2 rofecoxib, an NSAID, treatment following the injury, Group 3 rofecoxib treatment starting 24 hrs prior to the injury, Group 4 acetaminophen treatment following the injury. The muscle and the contralateral normal muscle were evaluated at 2, 5 and 7 days post-injury with grading of gait, wet weight and histology. RESULTS: Group 1 had significant more gait disturbances at day 2 than all other groups (P < 0.05). No differences were found at day 5 and 7. Wet weights showed an increase at day 2 in Group 1 (P < 0.01). Again no differences were at day 5 and 7. Histology revealed similar inflammatory changes at day 2 in all groups with regeneration of muscle fibers at day 5 and 7. CONCLUSION: The results of in this muscle injury study indicate that rofecoxib as an NSAID and acetaminophen as a non-NSAID analgesic have similar effects. The lack of differences in wet weights and histology suggest that the anti-inflammatory effects of rofecoxib are not an important feature of its action. Similarly, administration of the NSAID prior to the injury does not appear to enhance its effectiveness.