Prostaglandin biosynthesis inhibitors and endometriosis.

Prostaglandins (PGs) may be involved in the development of the symptoms of endometriosis. Therefore 18 patients with pelvic endometriosis were treated in placebo controlled double-blind trial with different prostaglandin biosynthesis inhibitors. These drugs were: acetylsalicylic acid (0.5 g x 3) exerting a weak PG-synthetase inhibition, indomethacin (25 mg x 3) inhibiting PG-synthetase, and as a representative of fenamates, tolfenamic acid (200 mg x 3), which both inhibits PG-synthetase and antagonizes PGs at the target level. The therapeutic effect was evaluated using a specific endometriosis score separately during menstruation and in premenstrum. Prostaglandin biosynthesis inhibitors did not alleviate premenstrual complaints better than placebo. During menstruation tolfenamic acid relieved endometriotic symptoms more effectively than placebo while indomethacin and acetylsalicylic acid did not differ from placebo. A drug which inhibit both the synthesis and action of PGs can thus be used in the alleviation of secondary dysmenorrhea due to endometriosis.