Dexamethasone Injection and Ulipristal: Interaction Details
AI-assisted, pharmacist-reviewed · Source data updated Aug 8, 2026 · Sources: FDA labeling, DDInter 2.0, cited literature
Ulipristal
Dexamethasone Injection
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 ulipristal exposure
Interaction Deep Dive
Avoid concomitant use of ulipristal, a CYP3A4 substrate, and a CYP3A4 inducer. Concomitant use of a ulipristal and a CYP3A4 inducer significantly decreased the plasma concentrations of ulipristal and its active metabolite due to induction of CYP3A4-mediated ulipristal metabolism, thereby decreasing its effectiveness3. In patients receiving a CYP3A4 inducer in need of emergency contraception, consider use of a copper intrauterine system (IUS); a double dose of oral ulipristal is not recommended 1.
Why it happens (mechanism)
Induction of CYP3A4-mediated metabolism of ulipristal
Literature reports
1 report — tap to read
a) A pharmacokinetic study demonstrated that 1 dose of ulipristal 30 mg when coadministered with the strong inducer rifAMPin 600 mg once daily for 9 days decreased the Cmax and AUC of ulipristal by 90% and 93%, respectively, and of its active metabolite, monodemethyl-ulipristal by 84% and 90%, respectively 3.
Common questions
Can I take Dexamethasone Injection and Ulipristal together?
Reduced ulipristal exposure Always confirm with your pharmacist or prescriber before making any change.
How serious is the Dexamethasone Injection 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 "unspecified". The timing of this interaction is not well characterized.
How strong is the evidence for this interaction?
The evidence is graded "theoretical". Predicted from the drugs' pharmacology; not yet confirmed in people.
Questions for your pharmacist
- Does my dose of Dexamethasone Injection 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)
- International Consortium for Emergency Contraception (ICEC): Emergency contraceptive pills: medical and service delivery guidance, 4th ed. Reproductive Health Supplies Coalition. Washington, DC. 2018.
- Sunaga T, Cicali B, Schmidt S, et al: Comparison of contraceptive failures associated with CYP3A4-inducing drug-drug interactions by route of hormonal contraceptive in an adverse event reporting system. Contraception 2021; 103(4):222-224. PubMed
- Product Information: ELLA(R) oral tablets, ulipristal acetate oral tablets. Afaxys, Inc. (per FDA), Charleston, SC, 2014. DailyMed
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