Side effects of the Yuzpe regimen of emergency contraception and two modifications.

We investigated side effects after the standard Yuzpe regimen or two modifications: substituting norethindrone as the progestin or eliminating the second dose. We also examined the impact of taking either dose with food. Nearly two thirds of women reported at least one side effect, the majority of which were mild or moderate. Women in our study experienced more side effects after the second dose than after the first. Taking the first dose within 1 h of a meal or snack was associated with increased nausea and vomiting; taking the second dose within 1 h of a meal or snack was associated with decreased nausea and vomiting. A targeted approach to prophylactic antiemetic use could reduce the number of women given these drugs, and the number who experience unnecessary side effects. The impact of counseling on side effects should be further evaluated.