What is the recommended dosing for Ella (ulipristal acetate) for emergency contraception?

Ella (Ulipristal Acetate) Dosing for Emergency Contraception

Ella (ulipristal acetate) should be administered as a single 30 mg oral dose as soon as possible and within 120 hours (5 days) after unprotected intercourse or contraceptive failure. 1, 2

Efficacy and Timing

• Ulipristal acetate prevents approximately 85% of expected pregnancies when used for emergency contraception 1
• Effective throughout the entire 120-hour window after unprotected intercourse 2
• More effective than levonorgestrel (Plan B) between days 3-5 after unprotected intercourse 1
• Clinical studies show:
  • When taken within 72 hours: reduces pregnancy rate from expected 5.6% to observed 1.9% 2
  • When taken between 48-120 hours: reduces pregnancy rate from expected 5.5% to observed 2.2% 2
  • No significant differences in efficacy across the five 24-hour intervals from 0 to 120 hours 2

Administration Instructions

• Take as a single oral dose of 30 mg
• No need for a second dose (unlike older levonorgestrel protocols that required two doses) 2
• Should be taken as soon as possible after unprotected intercourse for maximum efficacy 2
• Can be taken with or without food

Special Considerations

• BMI impact: May have reduced efficacy in women with BMI > 30 kg/m² (observed pregnancy rate 3.1% vs expected 4.5%) 2
• Menstrual effects: May delay onset of menses by approximately 2-3 days following treatment 3
• Requires a negative pregnancy test prior to administration 2
• Works primarily by inhibiting or delaying ovulation, particularly by delaying the LH surge or postponing LH peak 3

Comparative Efficacy

• More effective than levonorgestrel when used within 120 hours after unprotected intercourse 1, 4
• Meta-analysis showed ulipristal acetate had 42% lower pregnancy risk than levonorgestrel up to 72 hours and 65% lower risk in the first 24 hours 5
• Particularly advantageous for women seeking emergency contraception between 72-120 hours after unprotected intercourse, when levonorgestrel is less effective or not indicated 6

Common Side Effects

• Headache (19.3%)
• Nausea
• Abdominal pain 6

Ella represents an important emergency contraception option with the advantage of maintained efficacy throughout a longer window (120 hours) compared to levonorgestrel (72 hours), making it particularly valuable when patients present later after unprotected intercourse.