Drug interactions
Levonorgestrel + Lumacaftor / ivacaftor
Severity: Major
Levonorgestrel and Lumacaftor / ivacaftor: 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 lower exposure to hormonal contraceptives, so contraceptive effectiveness cannot be relied upon. Breakthrough bleeding and menstrual irregularities may also be more frequent during coadministration.
What this interaction means in plain words
Levonorgestrel and Lumacaftor / ivacaftor 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 CYP3A, increasing the metabolism of progestins and lowering their concentrations.
What to do
Advise an effective non-hormonal contraceptive method (e.g., copper IUD or condoms) during treatment. Do not rely on hormonal contraception alone.
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?
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Other interactions of Levonorgestrel
Frequently asked questions
Can I take Levonorgestrel with Lumacaftor / ivacaftor?
MediHelp rates the interaction as major. Levonorgestrel and Lumacaftor / ivacaftor 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 lower exposure to hormonal contraceptives, so contraceptive effectiveness cannot be relied upon. Breakthrough bleeding and menstrual irregularities may also be more frequent during coadministration.
How serious is the interaction between Levonorgestrel and Lumacaftor / ivacaftor?
MediHelp rates it major, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Advise an effective non-hormonal contraceptive method (e.g., copper IUD or condoms) during treatment. Do not rely on hormonal contraception alone.
What other medicines interact with Levonorgestrel?
MediHelp also lists interactions of Levonorgestrel with, for example, Amobarbital, Apalutamide, Belzutifan. The full list is on the Levonorgestrel page.
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