The effect of mefenamic acid on controlling irregular uterine bleeding secondary to Norplant use

The aim of this double-blind, placebo-controlled study was to evaluate the effect of mefenamic acid and placebo on controlling irregular uterine bleeding secondary to Norplant use. A total of 67 Norplant users attending the Family Planning Clinic of Chulalongkorn Hospital all had irregular bleeding. These women were randomly allocated into two groups. A total 34 users received mefenamic acid, 500 mg twice a day for 5 days, and placebos were given to the other 33 in the same manner. The total days of bleeding and spotting and the percentage of women in whom bleeding was stopped were analyzed in weeks 1 and 4. The percentage of subjects in whom bleeding was stopped during week 1 after initial treatment was significantly higher in the mefenamic acid group than the placebo group (76%, 27%; p < 0.001). In the follow-up period (4 weeks after initial treatment), a bleeding-free interval of > 20 days was found in 68% of the subjects treated with mefenamic acid and 33% treated with the placebo; the mean number of bleeding/spotting days was lower with mefenamic acid treatment (11.6 and 17.2 days; p < 0.05). The difference was statistically significant. It is concluded that mefenamic acid was more effective than placebo in short-term control of irregular bleeding and spotting associated with Norplant use.