, Volume 71, Issue 7, pp 935–945

Ulipristal Acetate

A Review of Its Use in Emergency Contraception
Adis Drug Evaluation


Ulipristal acetate (ellaOne®; ella®) is the first of a new class of selective progesterone receptor modulators, and is indicated for emergency contraception within 120 hours after unprotected sexual intercourse or contraceptive failure. The principal effect of ulipristal acetate is to inhibit or delay ovulation. This effect may result from the drug's ability to delay the onset of luteinizing hormone (LH) surge or postpone LH peak if LH surge has started, or possibly by a direct inhibitory effect on follicular rupture, when administered in the follicular phase (including just before ovulation).

In clinical trials, a single oral dose of ulipristal acetate 30 mg was effective in preventing pregnancies in women requesting emergency contraception after unprotected sexual intercourse and provided sustained efficacy throughout the 120-hour postcoital period in which it is indicated. When compared with levo-norgestrel in well designed noninferiority trials, it was no less effective in preventing pregnancies when administered within 72 hours of unprotected intercourse, but was more effective when administered later (within 72–120 hours). Results of a meta-analysis suggest that ulipristal acetate may be more effective than levo-norgestrel from day 1 and throughout the entire 5-day period following unprotected sexual intercourse.

Ulipristal acetate is generally well tolerated, with a similar tolerability profile to that of levonorgestrel. In general, the onset of menses is delayed by 2–3 days following treatment. Although, ulipristal acetate is more expensive than levonorgestrel, it may represent a cost-effective alternative to levonorgestrel for women requesting emergency contraception within 120 hours of unprotected intercourse. Thus, ulipristal acetate provides effective, sustained and well tolerated emergency contraception when taken within 120 hours of unprotected sexualintercourse, thereby offering an extended treatment window compared with levonorgestrel, which should be administered within 72 hours.


Unable to display preview. Download preview PDF.

Unable to display preview. Download preview PDF.


  1. 1.
    Gold RB, Sonfield A, Richards CL, et al. Next steps for America's family planning program: leveraging the potential of Medicaid and title X in an evolving health care system [online]. Available from URL: http://www.guttmacher.org/pubs/NextSteps.pdf [Accessed 2011 Mar 3]
  2. 2.
    Kishen M, Belfield T. Contraception in crisis. J Fam Plann Reprod Health Care 2006; 32(4): 211–2PubMedCrossRefGoogle Scholar
  3. 3.
    Trussell J, Ellertson C, von Hertzen H, et al. Estimating the effectiveness of emergency contraceptive pills. Contraception 2003; 67: 259–65PubMedCrossRefGoogle Scholar
  4. 4.
    Gemzell-Danielsson K. Mechanism of action of emergency contraception. Contraception 2010; 82: 404–9PubMedCrossRefGoogle Scholar
  5. 5.
    International Consortium for Emergency Contraception. What is emergency contraception? [online]. Available from URL: http://www.cecinfo.org/ [Accessed 2011 Mar 8]
  6. 6.
    Cremer M, Masch R. Emergency contraception: past, present and future. Minerva Ginecol 2010 Aug; 62(4): 361–71PubMedGoogle Scholar
  7. 7.
    Grimes D, Von Hertzen H, Piaggio G, et al. Randomised controlled trial of levonorgestrel versus Yuzpe regimen of combined oral contraceptives for emergency contraception. Task Force on Postovulatory Methods of Fertility Regulation. Lancet 1998 Aug; 352(9126): 428–33CrossRefGoogle Scholar
  8. 8.
    von Hertzen H, Piaggio G, Ding J, et al. Low dose mife-prestone and two regimens of levonorgestrel for emergency contraception: a WHO multicentre randomised trial. Lancet 2002 Dec 7; 360: 1803–10CrossRefGoogle Scholar
  9. 9.
    Cheng L, Gülmezoglu AM, Piaggio GGP, et al. Interventions for emergency contraception. Cochrane Database Syst Rev 2008 Apr 16; (2): CD001324Google Scholar
  10. 10.
    Plan B® One-Step (levonorgestrel) tablet 1.5 mg. US prescribing information. Pomona (NY): Barr Pharmaceuticals Inc., 2009Google Scholar
  11. 11.
    Gemzell-Danielsson K, Meng C-X. Emergency contraception: potential role of ulipristal acetate. Int J Womens Health 2010; 2(1): 53–61PubMedCrossRefGoogle Scholar
  12. 12.
    ella® (ulipristal acetate) tablet. US prescribing information. Morristown (NJ): Watson Pharma Inc., 2010Google Scholar
  13. 13.
    European Medicines Agency. Ulipristal acetate 30mg: summary of product characteristics [online]. Available from URL: http://www.http://www.ema.europa.eu/docs/en_GB/document_library/EPAR_-_Product_Information/human/001027/WC500023670.pdf [Accessed 2011 Feb 21]
  14. 14.
    Attardi BJ, Burgenson J, Hild SA, et al. CDB-4124 and its putative monodemethylated metabolite, CDB-4453, are potent antiprogestins with reduced antiglucocorticoid activity: in vitro comparison to mifepristone and CDB 2914. Mol Cell Endocrinol 2002; 188: 111–23PubMedCrossRefGoogle Scholar
  15. 15.
    Brache V, Cochon L, Jesam C, et al. Immediate pre-ovulatory administration of 30 mg ulipristal acetate significantly delays follicular rupture. Hum Reprod 2010; 25(9): 2256–63PubMedCrossRefGoogle Scholar
  16. 16.
    Palanisamy GS, Cheon Y-P, Kim J, et al. A novel pathway involving progesterone receptor, endothelin-2, and endothelin receptor B controls ovulation in mice. Mol Endocrinol 2006; 20(11): 2784–95PubMedCrossRefGoogle Scholar
  17. 17.
    Stratton P, Hartog B, Hajizadeh N, et al. A single midfollicular dose of CDB-2914, a new antiprogestin, inhibits folliculogenesis and endometrial differentiation in normally cycling women. Hum Reprod 2000; 15(5): 1092–9PubMedCrossRefGoogle Scholar
  18. 18.
    Croxatto HB, Brache V, Pavez M, et al. Pituitary-ovarian function following the standard levonorgestrel emergency contraceptive dose or a single 0.75-mg dose given on the days preceding ovulation. Contraception 2004; 70: 442–50PubMedCrossRefGoogle Scholar
  19. 19.
    Stratton P, Levens ED, Hartog B, et al. Endometrial effects of a single early luteal dose of the selective progesterone receptor modulator CDB-2914. Fertil Steril 2010 Apr; 93(6): 2035–41PubMedCrossRefGoogle Scholar
  20. 20.
    Passaro MD, Piquion J, Mullen N, et al. Luteal phase dose-response relationships of the antiprogestin CDB-2914 in normally cycling women. Hum Reprod 2003; 18(9): 1820–7PubMedCrossRefGoogle Scholar
  21. 21.
    Creinin MD, Schlaff W, Archer DF, et al. Progesterone receptor modulator for emergency contraception: a randomized controlled trial. Obstet Gynecol 2006 Nov; 108(5): 1089–97PubMedCrossRefGoogle Scholar
  22. 22.
    US FDA. Center for Drug Regulation and Research. Clinical pharmacology and biopharmaceutics review(s) [online]. Available from URL: http://www.accessdata.fda.gov/drugsatfda_docs/nda/2010/022474s000ClinPharmR.pdf [Accessed 2011 Apr 29]
  23. 23.
    Glasier AF, Cameron ST, Fine PM, et al. Ulipristal acetate versus levonorgestrel for emergency contraception: a randomised non-inferiority trial and meta-analysis. Lancet 2010 Feb 13; 375(9714): 555–62PubMedCrossRefGoogle Scholar
  24. 24.
    Fine P, Mathe H, Ginde S, et al. Ulipristal acetate taken 48–120 hours after intercourse for emergency contraception. Obstet Gynecol 2010 Feb; 115 (2 Pt 1): 257–63PubMedCrossRefGoogle Scholar
  25. 25.
    Trussell J, Rodriguez G, Ellertson C. New estimates of the effectiveness of the Yuzpe regimen of emergency contraception. Contraception 1998; 57: 363–9PubMedCrossRefGoogle Scholar
  26. 26.
    Thomas CM, Schmid R, Cameron S. Is it worth paying more for emergency hormonal contraception? The cost-effectiveness of ulipristal acetate versus levonorgestrel 1.5mg. J Fam Plann Reprod Health Care 2010; 36(4): 197–201PubMedCrossRefGoogle Scholar
  27. 27.
    Wilcox AJ, Weinberg CR, Baird DD. Timing of sexual intercourse in relation to ovulation. Effects on the probability of conception, survival of the pregnancy, and sex of the baby. N Engl J Med 1995; 333: 1517–21PubMedCrossRefGoogle Scholar
  28. 28.
    Faculty of Family Planning and Reproductive Health Care Clinical Effectiveness Unit. FFPRHC guidance (April 2006): emergency contraception. J Fam Plann Reprod Health Care 2006; 32(2): 121–8CrossRefGoogle Scholar

Copyright information

© Adis Data Information BV 2011

Authors and Affiliations

  1. 1.Adis, a Wolters Kluwer BusinessMairangi Bay, North Shore 0754, AucklandNew Zealand

Personalised recommendations