Nimesulide in dysmenorrhoea.

Nimesulide does not affect active intrauterine pressure, as measured using microsensors, or the direction and velocity of the propagation of uterine activity, but nevertheless alleviates pain significantly by 30 minutes after oral administration. In dysmenorrhoeic patients, resting pressure is high only in the fundus. Nimesulide reduces the pressure during the maximal but not during the submaximal pain period, with concomitant alleviation of pain. The drug changes the painful state of uterine contracture to painless cyclic contractions. With a single oral dose of 100mg, nimesulide is evenly distributed in female genital tissues (uterine fundus and cervix, oviduct and ovaries), reaching peak concentrations and peak plasma: tissue ratio (0.5) 3 hours after administration. Tissue concentrations range from 0.3 to 1.8 micrograms/g. Two 100mg oral doses of nimesulide administered to dysmenorrhoeic women in a double-blind placebo-controlled cross-over study reduced prostaglandin F2 alpha levels in menstrual blood from 382 to 94 micrograms/L. Double-blind placebo-controlled studies also confirmed that nimesulide relieves pain in dysmenorrhoeic patients.