Estradiol Transdermal Patch and Tocilizumab: Interaction Details
AI-assisted, pharmacist-reviewed · Source data updated Aug 8, 2026 · Sources: FDA labeling, DDInter 2.0, cited literature
Estradiol Transdermal Patch
Tocilizumab
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 oral contraceptives exposure and reduced efficacy of oral contraceptives
Interaction Deep Dive
Exercise caution when coadministering tocilizumab with oral contraceptives (CYP3A substrate) where decrease in effectiveness is undesirable. Concomitant use may also reduce tocilizumab exposure. Upon initiation or discontinuation of tocilizumab, in patients treated with oral contraceptives, perform therapeutic monitoring of effect or drug concentrations and the individual oral contraceptives dosage adjusted as needed. The effect of tocilizumab on CYP450 enzyme activity may persist for several weeks after stopping therapy1.
Why it happens (mechanism)
Induction of CYP3A4-mediated metabolism of oral contraceptives
Common questions
Can I take Estradiol Transdermal Patch and Tocilizumab together?
Reduced oral contraceptives exposure and reduced efficacy of oral contraceptives Always confirm with your pharmacist or prescriber before making any change.
How serious is the Estradiol Transdermal Patch and Tocilizumab 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 Estradiol Transdermal Patch or Tocilizumab 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 (1)
- Product Information: TOFIDENCE(TM) intravenous injection, tocilizumab-bavi intravenous injection. Biogen MA Inc (per FDA), Cambridge, MA, 2024. DailyMed
Keep reading about Estradiol Transdermal Patch
Keep reading about Tocilizumab
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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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