Objective: To determine whether rofecoxib is effective for treating primary dysmenorrhea and whether cyclooxygenase-2 is involved in the pathophysiology of primary dysmenorrhea.
Methods: A double-masked, randomized, placebo and active-comparator-controlled clinical trial including 127 subjects with histories of primary dysmenorrhea was conducted in an outpatient clinical research center. Subjects were randomly assigned to placebo, rofecoxib 25 or 50 mg followed by 25 mg every 24 hours as needed, or naproxen sodium 550 mg every 12 hours as needed for up to 3 days. Subjects took all four treatments in a balanced, complete-block, crossover design. Measurements included self-administered questionnaires of analgesic efficacy, spontaneous reports of adverse experiences, physical examinations, and laboratory safety tests.
Results: Rofecoxib 25 and 50 mg provided analgesic efficacy greater than placebo (P < or = .006) for the primary endpoint of total pain relief over the first 8 hours. For other efficacy endpoints (sum of the pain intensity difference over the first 8 hours, subject's global evaluation, peak pain relief, peak pain intensity difference, and time to remedication) both doses of rofecoxib were better than placebo (P < or = .006) and were not distinguishable from naproxen sodium for all efficacy endpoints. All treatments were well tolerated.
Conclusion: Rofecoxib effectively treated primary dysmenorrhea, and cyclooxygenase-2-derived prostanoids play a role in the pathophysiology of primary dysmenorrhea.