Ulipristal acetate (emergency contraceptive)
 BRAND NAMES
 MECHANISM OF ACTION
Ulipristal acetate (Ellaone, Ella) is a progesterone agonist/antagonist emergency contraceptive.
For pregnancy to occur there has to be ovulation (release of eggs) followed by the fertilisation of the egg (fusion with a sperm) and implantation in the womb. The sex hormone progesterone plays a role in the timing of ovulation and in preparing the lining of womb to receive the fertilised egg. Ulipristal acetate, acts as a progesterone receptor modulator. This means that it attaches to the receptors that progesterone normally attaches to, preventing the hormone from having its effect. When taken immediately before ovulation is to occur, Ulipristal acetate postpones follicular rupture. The likely primary mechanism of action of ulipristal acetate for emergency contraception is therefore inhibition or delay of ovulation; however, alterations to the endometrium that may affect implantation may also contribute to efficacy.
When taken within two days of unprotected sex or contraceptive failure, Ulipristal acetate was as effective as levonorgestrel (Norlevo) at preventing pregnancies.
Ulipristal acetate emergency contraceptive (Ellaone, Ella) is indicated for prevention of pregnancy following unprotected intercourse or a known or suspected contraceptive failure.
 DOSAGE FORMS AND STRENGTHS
30 mg tablet
One tablet taken orally as soon as possible, within 120 hours (5 days) after unprotected intercourse or a known or suspected contraceptive failure (such as a tear in a condom during sex). The tablet can be taken with or without food. If the woman vomits within three hours of taking the medicine she should take another tablet
Known or suspected pregnancy
- Ulipristal acetate is not indicated for termination of an existing pregnancy. Exclude pregnancy before administering
- Ectopic pregnancy: Women who become pregnant or complain of lower abdominal pain after taking Ulipristal acetate should be evaluated for ectopic pregnancy.
- Effect on menstrual cycle: Ulipristal acetate may alter the next expected menses. If menses is delayed beyond 1 week, pregnancy should be ruled out.
- Ulipristal acetate does not protect against STI/HIV.
Drugs or herbal products that induce CYP3A4 decrease the effectiveness of Ulipristal acetate
 PREGNANCY AND LACTATION
- Pregnancy Category X (US)
- Nursing mothers: Ulipristal acetate is not recommended for use by breastfeeding women.
 SIDE EFFECTS
The most common adverse reactions (≥ 5%) in the clinical trials were headache (18%), abdominal pain (12%), nausea (12%), dysmenorrhea (9%), fatigue (6%) and dizziness (5%)