Division of Pharmacy Practice, Arnold and Marie Schwartz College of Pharmacy and Health Sciences, Long Island University. NY, USA.
Clin Ther. 2012 Jan;34(1):24-36. doi: 10.1016/j.clinthera.2011.11.012. Epub 2011 Dec 9.
Emergency contraception (EC) is used to prevent unintended pregnancies. The current gold standard for oral EC is levonorgestrel (LNG) administered as a single 1.5-mg dose or in 2 doses of 0.75 mg separated by 12 hours. LNG has shown to be effective up to 72 hours after coitus. Ulipristal acetate (UPA) is a selective progesterone receptor modulator approved for EC use in the United States in August 2010. UPA is administered as a one-time, 30-mg dose within 120 hours of intercourse.
The goal of this review was to provide a summary of the available literature on the use of UPA for EC.
PubMed, Cochrane Library, ClinicalTrials.gov, International Pharmaceutical Abstracts, EBSCO, and Iowa Drug Information Service were searched from February 2011 through September 2011 to identify relevant articles. Search terms included ulipristal acetate, CDB-2914, VA 2914, and emergency contraception.
In an open-label study, UPA was effective in preventing pregnancy in 1241 women who presented for EC up to 120 hours (5 days) after unprotected intercourse, with an observed pregnancy rate of 2.1% (95% CI, 1.4%-3.1%) versus 5.5% (ie, the expected pregnancy rate without EC). The efficacy of UPA did not decrease significantly (P = 0.44) over time, with pregnancy rates at intervals between >48 and 72 hours at 2.3% (95% CI, 1.4%-3.8%), >72 and 96 hours at 2.1% (95% CI, 1.0%-4.1%), and >96 and 120 hours at 1.3% (95% CI, 0.1%-4.8%). In a single-blind, comparative noninferiority study of 1696 women, UPA was at least as effective as LNG when used within 72 hours for EC, with 15 pregnancies in the UPA group and 22 pregnancies in the LNG group (odds ratio = 0.68 [95% CI, 0.35-1.31]). In addition, UPA prevented significantly (P = 0.037) more pregnancies than LNG when used between 72 and 120 hours after unprotected intercourse, with 0 pregnancies in the UPA group and 3 pregnancies in the LNG group. In a meta-analysis, UPA prevented a greater percentage of pregnancies than LNG at intervals up to 24 hours (0.9% UPA vs 2.5% LNG; P = 0.035), up to 72 hours (1.4% UPA vs 2.2% LNG; P = 0.046), and up to 120 hours (1.3% UPA vs 2.2% LNG; P = 0.025). The most commonly (>10%) reported adverse events included headache, nausea, and abdominal pain. In addition, UPA delayed onset of menstruation by a mean of 2.1 to 2.8 days.
Based on clinical trials, UPA seems to be a reasonably tolerable and effective method of EC when used within 120 hours of intercourse. UPA is at least as effective as LNG when used within the first 72 hours after unprotected intercourse. However, UPA may be more effective than LNG when used between 72 to 120 hours after unprotected intercourse, extending the window of opportunity for EC. UPA may provide a new option for women who require EC up to 5 days after unprotected intercourse.
紧急避孕（EC）用于防止意外怀孕。目前口服 EC 的金标准是左炔诺孕酮（LNG），单次剂量 1.5 毫克或间隔 12 小时分 2 次服用 0.75 毫克。LNG 已证明在性交后 72 小时内有效。醋酸乌利司他（UPA）是一种孕激素受体选择性调节剂，于 2010 年 8 月在美国获准用于 EC。UPA 单次剂量为 30 毫克，在性交后 120 小时内使用。
本综述的目的是提供关于 UPA 用于 EC 的可用文献摘要。
从 2011 年 2 月至 2011 年 9 月，通过 PubMed、Cochrane 图书馆、ClinicalTrials.gov、国际药学文摘、EBSCO 和爱荷华药物信息服务搜索相关文章。搜索词包括乌利司他醋酸盐、CDB-2914、VA 2914 和紧急避孕。
在一项开放标签研究中，1241 名在无保护性交后 120 小时（5 天）内就诊的女性使用 UPA 进行 EC，妊娠率为 2.1%（95%CI，1.4%-3.1%），而未使用 EC 的预期妊娠率为 5.5%。随着时间的推移，UPA 的疗效没有显著下降（P=0.44），间隔>48 至 72 小时的妊娠率为 2.3%（95%CI，1.4%-3.8%），>72 至 96 小时为 2.1%（95%CI，1.0%-4.1%），>96 至 120 小时为 1.3%（95%CI，0.1%-4.8%）。在一项 1696 名女性的单盲、非劣效性比较研究中，UPA 在 72 小时内用于 EC 与 LNG 同样有效，UPA 组有 15 例妊娠，LNG 组有 22 例妊娠（比值比=0.68[95%CI，0.35-1.31]）。此外，与 LNG 相比，UPA 在无保护性交后 72 至 120 小时使用时显著（P=0.037）能预防更多的妊娠，UPA 组无妊娠，LNG 组有 3 例妊娠。在一项荟萃分析中，UPA 在直至 24 小时（0.9%UPA 与 2.5%LNG；P=0.035）、72 小时（1.4%UPA 与 2.2%LNG；P=0.046）和 120 小时（1.3%UPA 与 2.2%LNG；P=0.025）的时间间隔内，预防妊娠的百分比均高于 LNG。>10%的常见不良反应包括头痛、恶心和腹痛。此外，UPA 使月经平均推迟 2.1-2.8 天。
根据临床试验，在性交后 120 小时内使用 UPA 似乎是一种合理耐受和有效的 EC 方法。在无保护性交后 72 小时内使用时，UPA 与 LNG 同样有效。然而，与 LNG 相比，在无保护性交后 72 至 120 小时使用时，UPA 可能更有效，延长了 EC 的机会窗口。对于在无保护性交后 5 天内需要 EC 的女性，UPA 可能提供一种新的选择。
