What is the recommended use and dosage of ulipristal acetate (generic name) in women of reproductive age for emergency contraception or treatment of uterine fibroids?

Ulipristal Acetate: Clinical Applications and Dosing

Emergency Contraception

Ulipristal acetate 30 mg should be taken as a single oral dose within 120 hours (5 days) of unprotected intercourse, with sustained effectiveness throughout this entire window. 1, 2

Mechanism and Efficacy

• Ulipristal acetate works as a selective progesterone receptor modulator that inhibits or delays ovulation by delaying LH surge onset, postponing LH peak, or directly inhibiting follicular rupture when administered during the follicular phase 1, 3
• Clinical trials demonstrate a pregnancy rate reduction from an expected 5.5% to an observed 2.2% when taken 48-120 hours after intercourse, and from 5.6% to 1.9% when taken within 72 hours 2
• Ulipristal acetate maintains effectiveness throughout the full 120-hour window, unlike levonorgestrel which shows decreased effectiveness after 72 hours 1, 3

Comparative Effectiveness

• Ulipristal acetate is more effective than levonorgestrel when administered 72-120 hours after intercourse, and may be superior throughout the entire 5-day period 3
• For women with BMI >30 kg/m², ulipristal acetate may be more effective than levonorgestrel, though efficacy is reduced in both agents (observed pregnancy rate 3.1% vs expected 4.5% for ulipristal; 7.4% vs expected 4.4% for levonorgestrel) 1, 2
• The effectiveness hierarchy is: copper IUD (most effective) > ulipristal acetate > levonorgestrel > combined estrogen-progestin regimens 1

Post-Administration Contraception

• After using ulipristal acetate, barrier contraception or abstinence is required for 14 days or until the next menstrual period, whichever comes first, if starting regular hormonal contraception 1
• A pregnancy test is recommended if withdrawal bleeding does not occur within 3 weeks 1

---

Uterine Fibroids Treatment

For symptomatic uterine fibroids, ulipristal acetate 5-10 mg daily for 3-month courses achieves amenorrhea in 70-90% of patients and reduces fibroid volume by 45-72%, with applications both as preoperative therapy and long-term intermittent management. 4

Dosing and Treatment Courses

Preoperative Use (Women Desiring Future Fertility)

• Administer ulipristal acetate 5-10 mg daily for one 3-month course before myomectomy 4
• The 10 mg dose provides superior amenorrhea rates (83% vs 72% for 5 mg in first course) 5, 4
• Benefits include improved quality of life, fibroid shrinkage facilitating minimally invasive surgical approaches, and clinical benefits persisting up to 6 months after treatment cessation 4
• Median time to amenorrhea is 2-4 days, with rapid bleeding control 4

Long-Term Intermittent Therapy (Women Who Have Completed Childbearing)

• Initiate with 1-2 courses of ulipristal acetate 10 mg daily (3 months each), suspend treatment until symptoms recur, then consider additional 1-2 courses when symptoms return 4
• The 10 mg dose provides superior amenorrhea rates (55-57% vs 35-41% for 5 mg) in long-term use 4
• Each treatment course should be separated by at least one menstrual period before commencing the next course 5

Progressive Efficacy with Repeated Courses

• Fibroid volume reduction increases with successive courses: 45% after first course, 63% after second, 67% after third, and 72% after fourth course 5, 4
• Amenorrhea rates remain stable across courses: 83%, 82%, 78%, 75% for 10 mg dose across courses 1-4 5, 4
• Quality of life improvements are substantial, with 57% improvement in UFS-QOL activities subscale for 10 mg dose 4

Clinical Algorithm for Fibroid Management

• For FIGO type 0 or 1 (submucosal) fibroids with heavy menstrual bleeding: Consider ulipristal acetate as initial medical management before hysteroscopic myomectomy 5
• For reproductive-age patients with symptomatic fibroids desiring pregnancy: Use ulipristal acetate as preoperative therapy before laparoscopic or open myomectomy 5, 4
• For reproductive-age patients with symptomatic fibroids and no desire for future fertility: Trial medical management with ulipristal acetate before pursuing more invasive therapies 5
• Medical management should be trialed prior to pursuing invasive interventions in most cases 5

Safety Monitoring

Endometrial Changes (PAEC)

• Progesterone receptor modulator-associated endometrial changes (PAEC) occur in 16-26% of patients during treatment but are benign and reversible 4
• PAEC returns to normal histology in the majority of cases after treatment cessation (9% prevalence after course 4,6% after treatment cessation) 4
• No routine endometrial monitoring is required, but consider alternative treatments if PAEC persists or worsens 4

Hepatotoxicity Concerns

• Monitor liver function tests during treatment due to serious liver injury cases that have led to regulatory restrictions in some jurisdictions 4
• This represents the most significant safety concern limiting widespread use 4

Important Clinical Caveats

• Ulipristal acetate demonstrates noninferiority to leuprolide acetate for preoperative treatment but with superior tolerability (lower hot flash rates, no bone turnover impact, maintains estradiol at mid-follicular phase range) 6, 7
• Repeat workup is necessary if symptoms persist to ensure malignancy is not being missed 4
• For patients with infertility and submucosal fibroids undergoing IVF, ulipristal acetate achieved 41% fibroid volume reduction with pregnancy rates similar to matched controls without fibroids 5