Isotretinoin and Ethynodiol: Interaction Details
AI-assisted, pharmacist-reviewed · AI content regenerated Jul 11, 2026 · Source data updated Jul 2, 2026 · Sources: FDA labeling, DDInter 2.0, cited literature
Isotretinoin
Ethynodiol
No brand names on record
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.
Isotretinoin (Accutane and similar brands) is a powerful acne medicine, but it can cause very serious birth defects if you become pregnant while taking it. Ethynodiol is a progestin used in some hormonal birth control. The concern here is that your birth control may not work as reliably during isotretinoin treatment, and progestin-only "mini-pills" are especially not dependable.
The good news is that this is very manageable. Isotretinoin programs require using two forms of birth control at the same time. Please talk with your prescriber or pharmacist about the right combination for you so you stay fully protected.
Effect: Potential decreased contraceptive effectiveness when ethynodiol-containing hormonal contraceptives are used with isotretinoin.
- Mechanism: Unknown. PK/PD changes to estrogens/progestins are described as small but highly variable and unpredictable. Neither agent is a prodrug relevant here.
- Direction: Reduced contraceptive reliability; progestin-only/micro-dosed preparations carry higher failure risk.
- Evidence: Theoretical; supported by post-marketing pregnancy reports, more common with a single contraceptive method.
- Management: Per iPLEDGE-type requirements, use 2 concurrent effective contraceptive methods (or documented abstinence/hysterectomy). Counsel on pregnancy risk given isotretinoin teratogenicity.
What happens
Decreased effectiveness of hormonal contraceptives
Interaction Deep Dive
The pharmacokinetic and pharmacodynamic effects on estrogens and progestins when given together with isotretinoin are minor, yet they vary widely and cannot be reliably predicted. Cases of pregnancy have been documented in women relying on combined oral contraceptives, and also in those using topical, injectable, implantable, or insertable hormonal contraceptive products. These reports have been more common among individuals depending on only one contraceptive method. Micro-dosed progestin-only pills raise the likelihood of contraceptive failure when taken alongside isotretinoin. Throughout isotretinoin treatment, female patients who could become pregnant are required to use 2 methods of contraception at the same time, with one of those methods being: tubal ligation, a partner's vasectomy, intrauterine devices, birth control pills, or topical, injectable, implantable, or insertable hormonal birth control products123.
Why it happens (mechanism)
Unknown
How to manage this interaction
Keep using your birth control as prescribed, but understand that isotretinoin programs require an extra layer of protection because pregnancy during treatment carries a very high risk of serious birth defects.
- Use two forms of contraception at the same time throughout isotretinoin therapy (unless you have chosen absolute abstinence or have had a hysterectomy).
- One form should be a highly effective method such as an IUD, birth control pills, an implant/injection, tubal ligation, or a partner's vasectomy.
- Progestin-only "mini-pills" may not be enough on their own.
- Ask your prescriber or pharmacist to confirm your specific combination and review anything that could raise pregnancy risk.
Management is individual — confirm any change with your pharmacist or prescriber.
Literature reports
2 reports — tap to read
a) In one study, isotretinoin showed no interaction with oral contraceptives. Nine women receiving isotretinoin 0.5 mg/kg for severe pustular acne had been taking oral contraceptives (brand unknown) for at least three months before beginning isotretinoin therapy. As measured by radioimmunoassay, plasma levels of ethinyl estradiol and levonorgestrel were comparable in the control cycle and in two cycles following the initiation of isotretinoin 4.
b) When isotretinoin was administered together with a combination ethinyl estradiol/norethindrone product, the pharmacokinetic and pharmacodynamic changes were inconsistent and relatively small. In a single-center, open-label drug interaction study, 26 healthy women completed a study in which they received ethinyl estradiol/norethindrone oral contraceptive (OC) triphasic tablets (35 micrograms and 0.5/0.75/1 milligrams, respectively) each day. At the beginning of the third month, and after pregnancy had been excluded, participants additionally received isotretinoin 1 milligrams/kilogram/day in two divided doses to complete 16 to 20 weeks of isotretinoin treatment for severe, recalcitrant nodular acne. Plasma concentrations of ethinyl estradiol and norethindrone were slightly lower (9% and 11%, respectively) during the OC plus isotretinoin phase relative to the OC alone phase; however, variability among patients was high. Follicle stimulating hormone concentration fell 44% (p=0.03) with the addition of isotretinoin to the regimen, again with substantial variability; serum progesterone and luteinizing hormone levels remained unchanged. No pregnancies were reported 5.
Common questions
Can I take Isotretinoin and Ethynodiol together?
Birth control can be less reliable during isotretinoin, so use two effective methods at the same time and confirm your plan with your prescriber before starting treatment. Always confirm with your pharmacist or prescriber before making any change.
How serious is the Isotretinoin and Ethynodiol 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 is the Isotretinoin and Ethynodiol interaction managed?
Keep using your birth control as prescribed, but understand that isotretinoin programs require an extra layer of protection because pregnancy during treatment carries a very high risk of serious birth defects. Use two forms of contraception at the same time throughout isotretinoin therapy (unless you have chosen absolute abstinence or have had a hysterectomy). One form should be a highly effective… Management is individual — always follow your own care team's guidance.
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 Isotretinoin or Ethynodiol 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 (5)
- Product Information: Amnesteem(R) oral capsules, isotretinoin oral capsules. Mylan Pharmaceuticals Inc, Morgantown, WV, 2010. DailyMed
- Product Information: Claravis(TM) oral capsules, isotretinoin oral capsules. Barr Laboratories, Inc, Pomona, NY, 2010. DailyMed
- Product Information: Sotret(R) oral capsules, isotretinoin oral capsules. Ranbaxy Laboratories Inc. Jacksonville, FL, 2010. DailyMed
- Orme M, Back DJ, & Shaw MA: Isotretinoin and contraception. Lancet 1984; 2:752-753. PubMed
- Hendrix CW, Jackson KA, Whitmore E, et al: The effect of isotretinoin on the pharmacokinetics and pharmacodynamics of ethinyl estradiol and norethindrone. Clin Pharmacol Ther 2004; 75:464-75. PubMed
Keep reading about Isotretinoin
Keep reading about Ethynodiol
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