Medroxyprogesterone and Ulipristal: Interaction Details
AI-assisted, pharmacist-reviewed · Source data updated Aug 8, 2026 · Sources: FDA labeling, DDInter 2.0, cited literature
Ulipristal
Medroxyprogesterone
How we grade severity & evidence
Severity levels
- Contraindicated: These should generally not be used together.
- Major: Potentially serious — often needs a change or close monitoring.
- Moderate: Can be significant — usually manageable with monitoring.
- Minor: Usually limited clinical impact.
Evidence grades
- Established: Well documented — supported by controlled studies or strong clinical data.
- Probable: Good supporting evidence, though not definitively proven.
- Suspected: Some evidence suggests this interaction, but it is not well established.
- Possible: Limited or conflicting evidence; the interaction may occur.
- Theoretical: Predicted from the drugs' pharmacology; not yet confirmed in people.
Ratings come from the documented interaction literature and are reviewed by a pharmacist. They describe the documented risk of the combination, not what will necessarily happen to you — your dose, timing, and health picture all matter.
What happens
Reduced efficacy of ulipristal or progestin-based hormonal contraceptives
Interaction Deep Dive
Progestin-containing contraceptives may reduce ulipristal efficacy in delaying ovulation1, therefore efficacy for emergency contraception may be decreased if a progestogen was given within 7 days before ulipristal administration 2. Conversely, coadministration of ulipristal may reduce hormonal contraceptive efficacy 1. A combined or progestogen-only hormonal contraceptive method (except the levonorgestrel intrauterine system) may be initiated no sooner than 5 full days after using ulipristal (ie, on the sixth day after ulipristal emergency contraception was administered) 2. A reliable barrier method should also be used until the next menstrual period. Follow instructions on the initiation or resumption of specific hormonal contraceptives after ulipristal intake 1.
Why it happens (mechanism)
Competition for progesterone receptor binding
Literature reports
4 reports — tap to read
a) In clinical trials, ovulation rates were similar among women who started ethinyl estradiol 30 mcg/levonorgestrel 150 mcg (COC) within 1 day of ulipristal use during the follicular phase of the menstrual cycle vs women using placebo plus COC. Ovulation occurred in 33.3% of subjects who received ulipristal plus COC vs 32.4% of subjects who received placebo plus COC 3.
b) When a combined oral contraceptive containing ethinyl estradiol 30 mcg/levonorgestrel 150 mcg was started 2 days after ulipristal intake, the ability of ulipristal to delay ovulation, as assessed by transvaginal ultrasound, was reduced; follicular rupture occurred in 27% of subjects in less than 5 days, compared to 3% of subjects after ulipristal alone 1.
c) The effects on ovarian activity of delaying versus immediately resuming combination oral contraceptives (COCs) after ulipristal intake were investigated in women who had been using contraceptives containing ethinyl estradiol 30 mcg/levonorgestrel 150 mcg once daily for 21 days followed by 7 days of placebo pills for at least one cycle (N=49). All subjects missed 3 consecutive pills (Days 5 to 7) during the first week of pills in the subsequent cycle and took ulipristal on the following day (Day 8). These subjects were randomized to resume their COCs either on the same day as ulipristal intake vs 5 days later. No ovulations with potential risk of pregnancy occurred in either group in the 5 days following ulipristal. However, in the group that waited 5 days to resume taking COCs, 17.4% of women did ovulate later in the cycle (Days 18 to 26) whereas no ovulations occurred in the group that resumed COC intake on the same day as ulipristal 1.
d) Compared with women who used ulipristal alone, more women in the follicular phase of their menstrual cycle ovulated within 6 days of ulipristal use when they started desogestrel 75 mcg within a day of ulipristal intake. Conversely, ulipristal was associated with a reduction in the ability of desogestrel to inhibit cervical mucus permeability; thickening of cervical mucus was slowed by 3 to 4 days among patients who used ulipristal 2 days before desogestrel initiation compared with those who used desogestrel alone 3.
Common questions
Can I take Medroxyprogesterone and Ulipristal together?
Reduced efficacy of ulipristal or progestin-based hormonal contraceptives Always confirm with your pharmacist or prescriber before making any change.
How serious is the Medroxyprogesterone and Ulipristal interaction?
It is rated major. Potentially serious — often needs a change or close monitoring.
How quickly could this interaction happen?
The documented onset is "rapid". Effects can appear quickly, often within about 24 hours of combining the drugs.
How strong is the evidence for this interaction?
The evidence is graded "established". Well documented — supported by controlled studies or strong clinical data.
Questions for your pharmacist
- Does my dose of Medroxyprogesterone or Ulipristal need adjusting while I take them together?
- What symptoms should prompt me to call you or my prescriber right away?
- Does the timing of my doses matter for this combination?
- Is there a safer alternative to one of these medications for me?
References (3)
- Product Information: ELLA oral tablets, ulipristal acetate oral tablets. HRA Pharma America Inc (per FDA), Morristown, NJ, 2021. DailyMed
- International Consortium for Emergency Contraception (ICEC): Emergency contraceptive pills: medical and service delivery guidance, 4th ed. Reproductive Health Supplies Coalition. Washington, DC. 2018.
- Product Information: ELLA oral tablets, ulipristal acetate oral tablets. Afaxys, Inc. (per FDA), Charleston, SC, 2015. DailyMed
Keep reading about Ulipristal
Keep reading about Medroxyprogesterone
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