Clinical efficacy and differential inhibition of menstrual fluid prostaglandin F2alpha in a randomized, double-blind, crossover treatment with placebo, acetaminophen, and ibuprofen in primary dysmenorrhea.

Abstract

The purpose of this study was to compare acetaminophen with ibuprofen for pain relief and menstrual fluid prostaglandin F2alpha (PGF2alpha) suppression in primary dysmenorrhea. Twelve subjects were randomized to placebo, acetaminophen (1000 mg orally, 4 x daily for 3 days) or ibuprofen (400 mg orally, 4 x daily for 3 days), once during each cycle in a prospective, double-blinded, crossover study. Using preweighed super absorbent tampons, menstrual fluid was collected, extracted, and PGF2alpha radioimmunoassayed. Ten patients completed the study. Ibuprofen (P = .002) and acetaminophen (P = .022) were rated significantly better than placebo. Total menstrual fluid PGF2alpha with placebo was 36.2 + 6.1 microg but were 14.8 + 3.0 microg with ibuprofen (P = .001) and 21.4 + 3.4 microg with acetaminophen (P = .008). PGF2alpha concentrations with placebo were 0.34 + 0.054 microg/mL, with ibuprofen 0.16 + 0.026 microg/mL (P = .001), and with acetaminophen 0.23 + 0.029 microg/mL (P = .016). Both ibuprofen and acetaminophen were superior to placebo for pain relief and menstrual fluid PGF2alpha suppression, with ibuprofen being more potent.