Usage
Ulipristal acetate is prescribed for emergency contraception following unprotected sexual intercourse or contraceptive failure. It is also used for pre-operative treatment of moderate to severe symptoms of uterine fibroids in adult women of reproductive age. It is classified as a selective progesterone receptor modulator (SPRM). Ulipristal acetate primarily works by preventing or delaying ovulation. It may also alter the endometrium, making it less receptive to implantation.
Alternate Names
The International Nonproprietary Name (INN) is ulipristal acetate. A common brand name is ella®, ellaOne®.
How It Works
Pharmacodynamics: Ulipristal acetate exerts its contraceptive effect primarily through inhibiting or delaying ovulation. If ovulation has already occurred, it is no longer effective. It may also impact the endometrium, but this effect’s role in preventing pregnancy is uncertain.
Pharmacokinetics: Ulipristal acetate is rapidly absorbed after oral administration, reaching peak plasma concentration in about an hour. It has a half-life of approximately 32 hours. Primarily metabolized in the liver by CYP3A4 enzymes, with renal excretion being a minor pathway.
Mode of Action: Ulipristal acetate is a synthetic SPRM. It binds to the progesterone receptor, competing with progesterone. This action modifies the effects of progesterone, which are crucial for ovulation and endometrial receptivity.
Dosage
Standard Dosage
Adults:
A single 30 mg tablet taken orally as soon as possible within 120 hours (5 days) of unprotected intercourse or contraceptive failure.
Children (Postpubertal):
Same as adult dose.
Special Cases:
- Elderly Patients: Not intended for use in postmenopausal women.
- Patients with Renal Impairment: No specific dose adjustments for renal impairment.
- Patients with Hepatic Dysfunction: Use with caution in patients with severe liver disease.
- Patients with Comorbid Conditions: Use with caution in patients with severe asthma.
Clinical Use Cases
Ulipristal acetate is not indicated for use in clinical settings such as intubation, surgical procedures, mechanical ventilation, ICU use, or emergency situations like status epilepticus or cardiac arrest. Its use is strictly limited to emergency contraception and the pre-operative treatment of uterine fibroids.
Dosage Adjustments
No specific dosage adjustments are required based on renal or hepatic function. However, caution is advised in patients with severe hepatic dysfunction.
Side Effects
Common Side Effects:
Headache, nausea, abdominal pain, dysmenorrhea, changes in menstrual cycle (spotting, bleeding between periods, early or late period), dizziness, fatigue.
Rare but Serious Side Effects:
Severe lower abdominal pain (3 to 5 weeks after taking ulipristal), allergic reactions (rash, itching, hives, swelling of the eyes, face, tongue, throat), hepatic injury.
Long-Term Effects:
No significant long-term effects are known from a single dose for emergency contraception. Prolonged use for uterine fibroids requires liver monitoring due to the risk of hepatic injury.
Adverse Drug Reactions (ADR):
Angioedema, hepatic injury.
Contraindications
- Pregnancy (known or suspected)
- Hypersensitivity to ulipristal acetate
Drug Interactions
Ulipristal acetate interacts with several medications, including:
- CYP3A4 Inducers: (e.g., rifampicin, rifabutin, phenytoin, carbamazepine, St. John’s wort) reduce its effectiveness.
- CYP3A4 Inhibitors: (e.g., ketoconazole, itraconazole) may increase ulipristal levels.
- Hormonal Contraceptives: May reduce the effectiveness of both ulipristal and the hormonal contraceptive.
Pregnancy and Breastfeeding
Pregnancy: Contraindicated in pregnancy. FDA Pregnancy Category X.
Breastfeeding: Limited data suggest that ulipristal acetate and its metabolite are present in breast milk in small amounts. Some guidelines recommend expressing and discarding breast milk for 7 days, while others recommend continuing as normal or a shorter interruption based on pharmacokinetic data and low risk of infant exposure. Discuss options with a healthcare provider to balance the benefits of breastfeeding against the unknown risks of infant exposure.
Drug Profile Summary
- Mechanism of Action: Selective progesterone receptor modulator, inhibits or delays ovulation.
- Side Effects: Headache, nausea, abdominal pain, menstrual changes.
- Contraindications: Pregnancy.
- Drug Interactions: CYP3A4 inducers and inhibitors, hormonal contraceptives.
- Pregnancy & Breastfeeding: Contraindicated in pregnancy, caution advised during breastfeeding.
- Dosage: 30 mg single dose for EC. 5 mg once daily for up to 3 months for uterine fibroids.
- Monitoring Parameters: Liver function tests for prolonged use (uterine fibroids).
Popular Combinations
Ulipristal acetate is typically used as a single-dose medication and not in combination with other drugs for emergency contraception.
Precautions
- Not for routine contraception.
- Not for pregnancy termination.
- Does not protect against STIs.
- Liver function monitoring for prolonged use.
FAQs (Frequently Asked Questions)
Q1: What is the recommended dosage for Ulipristal acetate for emergency contraception?
A: A single 30 mg dose taken orally within 120 hours of unprotected intercourse or contraceptive failure.
Q2: How does Ulipristal acetate work?
A: It primarily works by preventing or delaying ovulation. It may also affect the endometrium.
Q3: Can Ulipristal acetate be used as regular contraception?
A: No, it is only for emergency contraception.
Q4: What are the common side effects?
A: Headache, nausea, abdominal pain, menstrual changes, dizziness, and fatigue.
Q5: Who should not take Ulipristal acetate?
A: Women who are pregnant or suspect they may be pregnant, and those with hypersensitivity to ulipristal acetate.
Q6: What should a patient do if they vomit within 3 hours of taking Ulipristal acetate?
A: They should consult a healthcare professional to consider repeating the dose.
Q7: Does Ulipristal acetate interact with other medications?
A: Yes, it can interact with certain drugs, including some antibiotics, antifungals, and herbal supplements like St. John’s wort. Consult a healthcare professional about potential drug interactions.
Q8: Can Ulipristal acetate be used while breastfeeding?
A: It’s best to discuss this with a healthcare professional. Some resources recommend interrupting breastfeeding for a period, while others deem it safe to continue based on available data. A risk-benefit assessment should be made.
Q9: What if a patient has liver problems?
A: Caution should be exercised in patients with severe liver disease. They should consult a healthcare provider.
Q10: How effective is Ulipristal acetate?
A: It is more effective the sooner it is taken after unprotected intercourse or contraceptive failure. Its efficacy may be reduced with increasing body weight or BMI. It is not effective if ovulation has already occurred.
