Continuous low-level topical heat in the treatment of dysmenorrhea

OBJECTIVE: To compare the efficacy of topically applied heat for menstrual pain with oral ibuprofen and placebo treatment. METHODS: We conducted a randomized placebo and active controlled (double dummy), parallel study using an abdominal patch (heated or unheated) for approximately 12 consecutive hours per day and oral medication (placebo or ibuprofen 400 mg) three times daily, approximately 6 hours apart for 2 consecutive days. Pain relief and pain intensity were recorded at 17 time points. There was at least 85% power to detect a true one-unit difference in the 2-day pain relief treatment means for comparisons with the unheated patch plus oral placebo group using a one-tailed test at the.05 level of significance, based on an observed within-group standard deviation of 1.147. RESULTS: Eighty-four patients were enrolled and 81 completed the study protocol. Over the 2 days of treatment, the heated patch plus placebo tablet group (mean 3.27, P <.001), the unheated patch plus ibuprofen group (mean 3.07, P =.001), and the combination heated patch plus ibuprofen group (mean 3.55, P <.001) had significantly greater pain relief than the unheated patch plus placebo group (mean 1.95). Greater pain relief was not observed for the combination heated patch plus ibuprofen group compared with the unheated patch plus ibuprofen group (P =.096); however, the time to noticeable pain relief was statistically significantly shorter for the heated patch plus ibuprofen group (median 1.5 hours) compared with the unheated patch plus ibuprofen group (median 2.79 hours, P =.01). CONCLUSION: Continuous low-level topical heat therapy was as effective as ibuprofen for the treatment of dysmenorrhea.