Menstrual prostaglandins and dysmenorrhea: modulation by non-steroidal antiinflammatory drugs.

The analgesic efficacy and tolerance of lysine clonixinate (LC) as well as LC-induced changes in menstrual prostaglandin levels were studied according to a prospective double-blind randomized crossover design, controlled with ibuprofen (I) and placebo (P). Treatment consisted in 4 consecutive phases : in the first phase, patients refrained from taking medication and during the remaining three phases, they received double-blind fixed doses of 1 tab let of lysine clonixinate 125 mg, l 400 mg or P, q.6h. at random, three day s before onset of menses and during 8 days thereafter. Controls were carrie d out at each menstrual cycle, assessing pain according to a scale from 0 t o 4, onset of premenstrual and intramenstrual symptoms, relief of pain and occurrence of side-effects. During menstruation, patients recorded their as sessments of pain in a diary and collected the whole menstrual bleeding dur ing the first three days. The intensity of menstrual pain remained unchange d in controls upon admission (3.16) and during the phase with no treatment (3.04), but was significantly reduced with P (2.4), LC (1.79) and 1 (1.54). Significantly lower pain intensities compared with placebo were seen with active treatment phases. Forty-two percent of patients treated with P repor ted premenstrual pain which was significantly reduced to 17% with LC and to 12.5% with I. Active treatment phases revealed 21% of asymptomatic patient s during premenstrual and menstrual periods and 71% (LC) and 75% (1) of cas es with partial relief of pain. Patients' diaries showed significant pain r eductions with LC and l, during the 1(st) and 2(nd) days compared with P; s uch differences were gradually reduced to nit by the 4(th) day. Levels of m enstrual PGs changed according to pain intensity reductions from baseline ( P: 29%, (NS); LC: 58% and l: 61%; both were statistically significant, p < 0.01).