A Cochrane review «»1 «...»1 included 18 studies with a total of 759 subjects. As a group, NDAIDs were more effective than placebo at reducing heavy menstrual bleeding but less effective than either tranexamic acid, danazol or the levonorgestrel releasing intrauterine system. Treatment with danazol caused a shorter duration of menstruation and more adverse events than NSAIDs but this did not appear to affect the acceptability of treatment. There were no statistically significant differences between NSAIDs and the other treatmanets (oral luteal progestogens, ethamsylate, an older progesterone releasing intra-uterine system and oral contraceptive pill), although these results were based on very small studies. There was no evidence of a difference between the individual NSAIDs (naproxen and mefenamic acid).