Endogenous prostaglandins in dysmenorrhea and the effect of prostaglandin synthetase inhibitors (PGSI) on uterine contractility.

The plasma concentration of 13,14-dihydro-PGF2 alpha during menstruation were determined by gas chromatography in 6 non-dysmenorrheic and 10 dysmenorrheic women. Nine out of 10 dysmenorrheic women were found to have increased levels (greater than 50 pg/ml) of the metabolite compared with mean level 25 pg/ml for non-dysmenorrheic women. All 9 women with elevated PGF2 alpha-metabolite levels responded favourably to treatment of dysmenorrhea with prostaglandin synthetase inhibitors. Determinations of PGF2 alpha in the endometrium carried out by gas chromatography-mass spectrometry showed 4 times higher concentrations in 5 dysmenorrheic women compared with 5 non-dysmenorrheic subjects. Treatment of dysmenorrhea with placebo or naproxen 250 mg and 500 mg in 6 patients resulted in decrease in tonus and amplitude of the contractions with a more rapid effect following administration of naproxen 500 mg while no effect was seen in 5 out of 6 patients following administration of placebo.