高剂量雌激素(含或不含孕激素)作为未避孕性交后的避孕措施已使用多年。针对这一适应证,现在,FDA批准了一种称作Preven的紧急避孕药盒上市。此药盒包括4片药物,每片含有50μg的已炔雌二醇和0.25mg的左炔诺孕酮,还有一次测试受孕的试剂用于排除已经受孕,且测试必须在服用Preven之前。 作用机制 性交后为了防止怀孕究竟要服用多大剂量的 High doses of estrogen (with or without progestin) have been used for many years as contraception after contraception. In response to this indication, the FDA has now approved the launch of an emergency contraceptive kit called Preven. The kit includes four tablets, each containing 50 μg of ethinyl estradiol and 0.25 mg of levonorgestrel, as well as one test of conception for pregnancy and one for test before taking Preven. Mechanism of sexual intercourse in order to prevent pregnancy exactly how much dose to take