Objective: We conducted a randomized trial to determine whether pretreatment with meclizine reduces the incidence of nausea and vomiting associated with the Yuzpe regimen of emergency contraception.
Methods: We randomly assigned 343 women aged 18-45 years who were not at risk for pregnancy to pretreatment with 50 mg of meclizine, placebo, or no drug 1 hour before the first of two doses of emergency contraceptive pills. We asked participants to complete three questionnaires over the following 48 hours.
Results: The incidence of nausea was 47% in the group pretreated with meclizine and 64% in the other two groups (relative risk adjusted for center 0.7, 95% confidence intervals 0.6, 0.9 for comparisons of meclizine with both placebo and no drug). The severity of nausea and the incidence of vomiting were also significantly lower in the meclizine pretreatment group than in the other two groups. Drowsiness was reported by about twice as many women in the meclizine pretreatment group (31%) than in the other two groups (13% in the placebo group, 16% in the no-pretreatment group; P < .01 for both comparisons).
Conclusion: Meclizine is effective for preventing nausea and vomiting associated with the Yuzpe regimen of emergency contraceptive pills. Women using this drug should be cautioned to anticipate drowsiness.