Manufacturer:
Watson Pharmaceuticals, Inc.
Pharmacological Class:
Progesterone agonist/antagonist.
Active Ingredient(s):
Ulipristal acetate 30mg; tab.
Indication(s):
Prevention of pregnancy following unprotected intercourse or known or suspected contraceptive failure. Not for use as regular contraceptive.
Pharmacology:
Ulipristal acetate is a synthetic progesterone agonist/antagonist that can reduce the risk of pregnancy if taken up to 5 days after unprotected intercourse or contraceptive failure. When taken immediately before ovulation, it postpones follicular rupture. The likely primary mechanism of action for emergency contraception is inhibition or delay of ovulation; however, changes to the endometrium that inhibit implantation may contribute to its efficacy. The timing of administration in the menstrual cycle affects the effect of the drug on the reproductive system. If taken in the mid-follicular phase, it causes inhibition of folliculogenesis and reduction of estradiol concentration. If taken at the time of peak luteinizing hormone levels, follicular rupture is delayed by 5–9 days. Dosing in the early luteal phase does not significantly delay endometrial maturation but decreases endometrial thickness.
Clinical Trials:
Two studies were undertaken to assess the safety and efficacy of ulipristal acetate 30mg for emergency contraception. Women in both studies were required to have a negative pregnancy test before receiving emergency contraception. Primary efficacy analyses were performed on subjects <36 years of age who had a known pregnancy status after taking study medication.
In an open-label study, healthy women (mean age 24 years) who requested emergency contraception 48–120 hours after unprotected intercourse were given a 30mg dose of ulipristal. The median body mass index (BMI) in this study was 25.3 (range 16.1–61.3kg/m2). The use of ulipristal significantly reduced the pregnancy rate, from an expected 5.5% to an observed 2.2%, when it was taken 48–120 hours after unprotected intercourse. Of 1242 women evaluated, 27 pregnancies occurred.
In a single-blind comparison study, healthy women (mean age 25 years) who requested emergency contraception within 120 hours of unprotected intercourse were randomly assigned to receive either levonorgestrel 1.5mg or ulipristal 30mg. The median BMI was 25.3 (range 14.9–70kg/m2). Of 844 women 16–35 years of age in the group given ulipristal, 16 pregnancies occurred when emergency contraception was taken 0 to 72 hours after unprotected intercourse. The use of ulipristal significantly reduced the pregnancy rate, from an expected 5.6% to an observed 1.9% when taken within 72 hours of unprotected intercourse. There were no pregnancies in those patients who took ulipristal >72 hours after unprotected intercourse.
Subgroup analysis of the pooled data showed that for women with BMI >30kg/m2 the observed pregnancy rate with both ulipristal and levonorgestrel was not significantly different from the expected pregnancy rate for no treatment.
The safety and efficacy of ulipristal acetate if used more than once within the same menstrual cycle has not been evaluated, so its repeated use within the same cycle is not recommended.
Legal Classification:
Rx
Adults:
Take 1 tablet as soon as possible within 120 hrs (5 days) after unprotected intercourse or contraceptive failure. May repeat dose if vomiting occurs within 3 hrs.
Children:
Premenarchal: not applicable.
Contraindication(s):
Known/suspected pregnancy (Cat.X).
Warnings/Precautions:
Rule out ectopic pregnancy if lower abdominal pain occurs. Rule out pregnancy if subsequent menses delayed by >1 week. Does not protect against STDs/HIV (AIDS). Postmenopausal women, nursing mothers: not recommended.
Interaction(s):
Drugs (eg, barbiturates, bosentan, carbamazapine, felbamate, griseofulvin, oxcarbazepine, phenytoin, rifampin, topiramate) or herbals (eg, St. John’s wort) that induce certain enzymes (eg, CYP3A4) may decrease effectiveness. May be potentiated by CYP3A4 inhibitors (eg, ketoconazole, itraconazole). May antagonize regular hormonal contraceptives; use barrier contraception for remainder of menstrual cycle.
Adverse Reaction(s):
Headache, abdominal pain, nausea, dysmenorrhea, fatigue, dizziness; menstrual cycle changes.
How Supplied:
Tab—1