Valdecoxib, a cyclooxygenase-2-specific inhibitor, is effective in treating primary dysmenorrhea.

Objective: To compare the efficacy of the cyclooxygenase (COX)-2-specific inhibitor valdecoxib with naproxen sodium in treating menstrual pain associated with primary dysmenorrhea.

Method: This single-center, double-blind, placebo-controlled, randomized, crossover study compared the efficacy and safety of single oral doses of valdecoxib 20 mg and 40 mg with naproxen sodium 550 mg, or placebo, with an option of treatment for up to 3 days, twice daily. Efficacy was assessed by time-weighted sum of total pain relief, sum of pain intensity difference, time-specific pain relief, and pain intensity difference over 12 hours, time to rescue medication or first re-medication, the percentage of patients taking rescue medication, and patient's global evaluation of study medication.

Results: Mean time-weighted sum of total pain relief and sum of pain intensity difference were significantly superior to placebo for the first 8 and 12 hours after the initial dose of valdecoxib 20 mg (P <.01) and 40 mg (P <.001). Valdecoxib 20 mg and 40 mg were comparable to naproxen sodium 550 mg for all efficacy measures. Other differences in efficacy measures favoring the higher dose of valdecoxib did not achieve statistical significance, with the exception of sum of pain intensity difference-12. Both doses of valdecoxib were well tolerated.

Conclusions: Both valdecoxib 20- and 40-mg doses were effective and well tolerated for the treatment of primary dysmenorrhea. Valdecoxib 20 mg and 40 mg demonstrate analgesic efficacy, based on onset, magnitude, and duration of analgesia that is similar to naproxen sodium, making it a potential choice for treating women with primary dysmenorrhea.