Nomegestrol and Isotretinoin: 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
Nomegestrol
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.
This one is really important if you can become pregnant. Isotretinoin (Accutane and similar brands) is a powerful acne medicine that can cause serious birth defects if you get pregnant while taking it. Nomegestrol is a progestin hormone used for birth control.
The concern is that isotretinoin may make hormonal birth control less reliable, and the effect is small but hard to predict. Pregnancies have happened in people using only one method. Because of this, anyone who can become pregnant needs to use two forms of birth control at the same time during isotretinoin treatment. Please talk with your doctor or pharmacist so they can set up a safe plan with you.
Effect: Potential decreased contraceptive efficacy of the progestin (nomegestrol) during isotretinoin therapy.
- Mechanism: Unknown. PK/PD changes to estrogens/progestins are small but highly variable and unpredictable. Neither agent is dependent on the other for activation.
- Direction: Reduced contraceptive reliability; contraceptive failure/pregnancy reported.
- Evidence: Theoretical, but severity is major given isotretinoin's teratogenicity.
- Management: Require two simultaneous contraceptive methods unless absolute abstinence or hysterectomy. Micro-dosed progestin-only preparations may be inadequate. Counsel on pregnancy-risk behaviors and adhere to iPLEDGE requirements.
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 taking combined oral contraceptives, along with those using topical, injectable, implantable, or insertable hormonal birth control products. These cases have been more common among individuals relying on only one contraceptive method. The likelihood of contraceptive failure is increased by micro-dosed progestin-only pills when used alongside isotretinoin. Throughout isotretinoin treatment, female patients capable of becoming pregnant are required to use 2 contraceptive methods at the same time, with one of these being: tubal ligation, a partner's vasectomy, intrauterine devices, birth control pills, or topical/injectable/implantable/insertable hormonal birth control products123.
Why it happens (mechanism)
Unknown
How to manage this interaction
Keep taking both exactly as prescribed, but do not rely on birth control alone. Because isotretinoin can seriously harm a pregnancy and may make hormonal contraception less reliable, your care team will typically:
- Have you use two forms of contraception at the same time (unless you have chosen complete abstinence or have had a hysterectomy).
- Note that progestin-only "mini-pills" may not be enough on their own.
- Counsel you on avoiding behaviors that raise pregnancy risk, and follow any required pregnancy-testing program.
Ask your pharmacist or prescriber to confirm your exact contraception plan before starting isotretinoin.
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 concentrations of ethinyl estradiol and levonorgestrel in the control cycle and in two cycles following the start of isotretinoin were comparable 4.
b) When isotretinoin was administered with a combination ethinyl estradiol/norethindrone product, the pharmacokinetic and pharmacodynamic changes were inconsistent and relatively minor. In a single-center, open-label drug interaction study, 26 healthy women completed a protocol in which they received ethinyl estradiol/norethindrone oral contraceptive (OC) triphasic tablets (35 micrograms and 0.5/0.75/1 milligrams, respectively) each day. Beginning at the start of the third month, after pregnancy was excluded, participants also 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 than during the OC alone phase; however, patient variability was high. Follicle stimulating hormone concentration fell by 44% (p=0.03) when isotretinoin was added to the regimen, once more with substantial variability; serum progesterone and luteinizing hormone levels remained unchanged. No pregnancies were reported 5.
Common questions
Can I take Nomegestrol and Isotretinoin together?
Isotretinoin can make hormonal birth control less reliable, so if you can become pregnant you must use two forms of contraception at the same time during treatment and confirm your plan with your prescriber. Always confirm with your pharmacist or prescriber before making any change.
How serious is the Nomegestrol and Isotretinoin 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 Nomegestrol and Isotretinoin interaction managed?
Keep taking both exactly as prescribed, but do not rely on birth control alone. Because isotretinoin can seriously harm a pregnancy and may make hormonal contraception less reliable, your care team will typically: Have you use two forms of contraception at the same time (unless you have chosen complete abstinence or have had a hysterectomy). Note that progestin-only "mini-pills" may not be enough… 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 Nomegestrol or Isotretinoin 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 Nomegestrol
These medications also interact with supplements
Prescription drugs aren't the whole picture — herbal and dietary supplements can interact with them too. From the evidence-graded Natural Medicines database:
major · moderate · minor — check everything you take with our drug–supplement interaction checker.
Check another combination
Our instant two-drug interaction checker is almost here.
Still have questions about this combination?
Every question gets a real answer from a licensed pharmacist — free, and usually within a day.
Ask the pharmacist