The Effect of an H₁ Blocker, Chlorpheniramine Maleate, on Total Menstrual Loss

50 subjects participated in a 4-month study of the effects of an antihistamine on total menstrual loss. During the first 2 periods, no drugs were given; during the last 2 periods, an antihistamine or a placebo was administered according to a double-blind format. The menstrual weights of the first 2 months were averaged and compared with averages from the last 2 months combined. The treated group showed an average decrease in menstrual loss of 11.30 g compared to a decrease of 0.98 g in the placebo group. While the difference in means was not statistically significant, the variance between the 2 groups was significant (p = 0.0002), indicating that the antihistamine, chlorpheniramine maleate, was effective in reducing menstrual loss in certain individuals, but that the effect was neither uniform nor universal.