Dabrafenib and Estradiol: Interaction Details
AI-assisted, pharmacist-reviewed · Source data updated Aug 8, 2026 · Sources: FDA labeling, DDInter 2.0, cited literature
Dabrafenib
Estradiol
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 hormonal contraceptive exposure, reduced efficacy of hormonal contraceptives and increased risk of breakthrough bleeding and/or contraceptive failure
Interaction Deep Dive
Avoid concomitant use of dabrafenib and hormonal contraceptives1, as it may reduce the plasma concentrations of the contraceptives and render them ineffective. Because dabrafenib can cause fetal harm, advise patient to use nonhormonal forms of contraception 4 or a back-up method during coadministration and for at least 28 days after discontinuation of a CYP3A4 inducer, such as dabrafenib 3. If concomitant use is unavoidable, monitor for loss of efficacy of the hormones 4. In a study, concomitant use of a CYP3A4 inducer disproportionally increased the rate of unplanned pregnancy with oral and implanted contraceptives; therefore, consider intrauterine or intravaginal routes if coadministration is required 2.
Why it happens (mechanism)
Induction of CYP3A4-mediated metabolism of hormonal contraceptives
Literature reports
1 report — tap to read
a) Concomitant use of a CYP3A4 inducer with oral or implantable contraceptive products containing levonorgestrel (684 events) or etonogestrel/desogestrel (864 events) was associated with a disproportionately higher rate of unintended pregnancy compared to all other event types reported to the FDA Adverse Event Reporting System (FAERS) between 1971 and 2020 [levonorgestrel (14,504 total events); etonogestrel/desogestrel (9348 total events)]. When compared between CYP3A4 inducer exposure vs no exposure, cases of unintended pregnancy made up a significantly higher proportion of total events when levonorgestrel was administered orally (32.8% vs 10.5%) or as an implant (51.9% vs 11.9%), and a similar association was identified with implanted etonogestrel products (42.5% vs 13.1%). However, when contraceptives were administered as an intrauterine device (levonorgestrel, 10.3% vs 11.5%) or intravaginal ring (etonogestrel, 10.9% vs 8.7%), no significant associations were identified. Oral desogestrel (pro-drug of etonogestrel) in combination with ethynyl estradiol also was not significantly affected (11.8% vs 17.4%). Intrauterine and vaginal ring products may be preferred in lieu of oral and implantable contraceptive products in women concomitantly receiving CYP3A4 inducers 2.
Common questions
Can I take Dabrafenib and Estradiol together?
Reduced hormonal contraceptive exposure, reduced efficacy of hormonal contraceptives and increased risk of breakthrough bleeding and/or contraceptive failure Always confirm with your pharmacist or prescriber before making any change.
How serious is the Dabrafenib and Estradiol 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.
From our Q&A
Real reader questions about these medications, each personally answered by our pharmacist:
Questions for your pharmacist
- Does my dose of Dabrafenib or Estradiol 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 (4)
- Product Information: FEMLYV orally disintegrating tablets, norethindrone acetate, ethinyl estradiol orally disintegrating tablets. Millicent U.S. Inc (per FDA), East Hanover, NJ, 2024. DailyMed
- 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: SLYND oral tablets, drospirenone oral tablets. Exeltis USA Inc (per FDA), Florham Park, NJ, 2019. DailyMed
- Product Information: TAFINLAR(R) oral capsules, tablets for suspension, dabrafenib oral capsules, tablets for suspension. Novartis Pharmaceuticals Corporation (per FDA), East Hanover, NJ, 2023. DailyMed
Keep reading about Dabrafenib
Keep reading about Estradiol
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.
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