A double-blind comparison of a propionic acid derivative (ibuprofen) and a fenamate (mefenamic acid) in the treatment of dysmenorrhea.

A double-blind three-way crossover design in the treatment of dysmenorrhea comparing a propionic acid derivative (ibuprofen) and a fenamate (mefenamic acid) with a placebo showed that both ibuprofen and mefenamic acid are generally superior to placebo. Statistically significant results were obtained in favor of the study drugs over placebo for the pain relief afforded by the treatments (as graded by patients) and the visual analog pain relief score, which not only ranks but also indicates the degree of pain relief as a percentage of total relief (100%). Pairwise comparisons for the ranks found mefenamic acid significantly superior to placebo (P less than .001) and ibuprofen marginally superior to placebo (P less than .06), while the visual analog pain relief scale demonstrated mefenamic acid and ibuprofen superior to placebo (P less than .001 and P less than .01, respectively). For both the patient ranking of pain relief by treatment and the visual analog pain relief scale, the results showed no significant differences between ibuprofen and mefenamic acid. Side effects occurred in 11 ibuprofen cycles, five mefenamic acid cycles, and ten placebo cycles of the 48 cycles with each agent. These were generally of minor severity or importance and were not statistically different. The need for additional analgesics and the ability to pursue normal daily activity were not different for any treatment group. The findings of this study indicate no clinical difference between a propionic acid derivative such as ibuprofen and a fenamate such as mefenamic acid in the treatment of dysmenorrhea.