Drug interactions
Isoniazid + Ivacaftor
Severity: Moderate
Isoniazid and Ivacaftor: moderate 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
Ivacaftor is a sensitive CYP3A substrate, and CYP3A inhibitors can substantially increase its exposure, raising the risk of adverse effects such as transaminase elevation. Isoniazid inhibits CYP3A only weakly to moderately, so the effect is likely smaller than with azole antifungals. Isoniazid is also hepatotoxic, which adds to concern about liver injury.
What this interaction means in plain words
Isoniazid and Ivacaftor can affect each other. The combination is often manageable, but it may need a change of dose, a change of timing, or extra checks while both are taken.
Isoniazid belongs to Anti Bacterial; Ivacaftor belongs to Miscellaneous.
Why it happens
Isoniazid inhibits CYP3A4, reducing the metabolism of ivacaftor.
What to do
Monitor liver enzymes and consider reducing the ivacaftor dose per product labeling. Watch for headache, abdominal pain and elevated transaminases.
What to ask your pharmacist
- Should I take them at different times of day?
- Does the dose of either medicine need to change?
- Is there anything I should avoid, such as alcohol or certain foods, while on both?
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Other interactions of Isoniazid
Other interactions of Ivacaftor
- Ensitrelvir + Ivacaftor Contraindicated
- Apalutamide + Ivacaftor Major
- Carbamazepine + Ivacaftor Major
- Clarithromycin + Ivacaftor Major
- Efavirenz + Ivacaftor Major
- Enzalutamide + Ivacaftor Major
Frequently asked questions
Can I take Isoniazid with Ivacaftor?
MediHelp rates the interaction as moderate. Isoniazid and Ivacaftor can affect each other. The combination is often manageable, but it may need a change of dose, a change of timing, or extra checks while both are taken. Ivacaftor is a sensitive CYP3A substrate, and CYP3A inhibitors can substantially increase its exposure, raising the risk of adverse effects such as transaminase elevation. Isoniazid inhibits CYP3A only weakly to moderately, so the effect is likely smaller than with azole antifungals. Isoniazid is also hepatotoxic, which adds to concern about liver injury.
How serious is the interaction between Isoniazid and Ivacaftor?
MediHelp rates it moderate, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Monitor liver enzymes and consider reducing the ivacaftor dose per product labeling. Watch for headache, abdominal pain and elevated transaminases.
What other medicines interact with Isoniazid?
MediHelp also lists interactions of Isoniazid with, for example, Bacillus calmette-guerin substrain tice, Benzhydrocodone / acetaminophen, Carbamazepine. The full list is on the Isoniazid page.
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