What is the role of Ulipristal in emergency contraception?

Updated: Oct 06, 2020
  • Author: Frances E Casey, MD, MPH; Chief Editor: Richard Scott Lucidi, MD, FACOG  more...
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Ulipristal is a selective progesterone receptor modulator with antagonistic and partial agonistic effects. When taken immediately before ovulation, ulipristal postpones follicular rupture and works through the LH surge. It is thought that the primary mechanism of action for emergency contraception is inhibition or delay of ovulation; however, alterations to the endometrium that may affect implantation may also occur. The treatment regimen is 30 mg (1 tablet) PO as soon as possible (within 120 hours [5 days]) after unprotected intercourse or a known/suspected contraceptive failure. If vomiting occurs within 3 hours after the dose, consider repeating the regimen. [36]

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