Drug interactions
Lumacaftor / ivacaftor + Norethisterone
Severity: Major
Lumacaftor / ivacaftor and Norethisterone: major interaction.
Last updated
For healthcare professionals — reference only. This page is a brief summary, not medical advice and not a substitute for official labeling or clinical judgement. Always verify before prescribing or dispensing.
Summary
Lumacaftor is a strong CYP3A inducer and can reduce norethisterone exposure. Hormonal contraceptives may become unreliable, and menstrual irregularities are more common.
What this interaction means in plain words
Lumacaftor / ivacaftor and Norethisterone can interact in a way that may be serious. Using them together is sometimes necessary, but it needs a deliberate decision by the prescriber, a plan for monitoring, and clear advice on the warning signs to watch for.
Why it happens
Lumacaftor induces CYP3A4, increasing norethisterone clearance.
What to do
Do not rely on hormonal contraception alone during treatment; use a nonhormonal method such as a copper IUD or barrier methods. Counsel the patient about breakthrough bleeding as a sign of reduced exposure.
What to ask your pharmacist
- Does the benefit of taking both outweigh the risk in my case?
- Do I need any blood test, ECG or other check while on both?
- What early warning signs should I watch for, and what should I do if they appear?
Pro+ members
Unlock the full page
Create an account and start a Pro+ trial to unlock the full management advice for Lumacaftor / ivacaftor and Norethisterone, the additional notes, the evidence detail and the whole-prescription interaction checker.
- Full clinical management advice
- Additional notes
- Evidence detail
- Interaction checker for a whole prescription
Try Pro+ free for 7 days on the web. No card needed.
Other interactions of Norethisterone
- Acitretin + Norethisterone Contraindicated
- Amobarbital + Norethisterone Major
- Apalutamide + Norethisterone Major
- Belzutifan + Norethisterone Major
- Bosentan + Norethisterone Major
- Brigatinib + Norethisterone Major
Frequently asked questions
Can I take Lumacaftor / ivacaftor with Norethisterone?
MediHelp rates the interaction as major. Lumacaftor / ivacaftor and Norethisterone can interact in a way that may be serious. Using them together is sometimes necessary, but it needs a deliberate decision by the prescriber, a plan for monitoring, and clear advice on the warning signs to watch for. Lumacaftor is a strong CYP3A inducer and can reduce norethisterone exposure. Hormonal contraceptives may become unreliable, and menstrual irregularities are more common.
How serious is the interaction between Lumacaftor / ivacaftor and Norethisterone?
MediHelp rates it major, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Do not rely on hormonal contraception alone during treatment; use a nonhormonal method such as a copper IUD or barrier methods. Counsel the patient about breakthrough bleeding as a sign of reduced exposure.
What other medicines interact with Norethisterone?
MediHelp also lists interactions of Norethisterone with, for example, Acitretin, Amobarbital, Apalutamide. The full list is on the Norethisterone page.
Full monographs, dosing and an interaction checker in the MediHelp app
Open the complete reference, check multi-drug interactions and use dosing tools in the MediHelp app.
