Drug interactions
Isoniazid + Lonafarnib
Severity: Major
Isoniazid and Lonafarnib: 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
Lonafarnib is a sensitive CYP3A4 substrate, so even modest inhibition can raise its exposure and increase adverse effects such as gastrointestinal toxicity, myelosuppression, and hepatotoxicity. Isoniazid is a weak-to-moderate inhibitor.
What this interaction means in plain words
Isoniazid and Lonafarnib 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.
Isoniazid belongs to Anti Bacterial; Lonafarnib belongs to Miscellaneous.
Why it happens
Inhibition of CYP3A4 metabolism of lonafarnib.
What to do
Avoid if possible; if combined, monitor for lonafarnib toxicity including liver tests and blood counts and reduce the dose per labeling.
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 Isoniazid
Other interactions of Lonafarnib
- Alfuzosin + Lonafarnib Contraindicated
- Amobarbital + Lonafarnib Contraindicated
- Apalutamide + Lonafarnib Contraindicated
- Bosentan + Lonafarnib Contraindicated
- Carbamazepine + Lonafarnib Contraindicated
- Clarithromycin + Lonafarnib Contraindicated
Frequently asked questions
Can I take Isoniazid with Lonafarnib?
MediHelp rates the interaction as major. Isoniazid and Lonafarnib 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. Lonafarnib is a sensitive CYP3A4 substrate, so even modest inhibition can raise its exposure and increase adverse effects such as gastrointestinal toxicity, myelosuppression, and hepatotoxicity. Isoniazid is a weak-to-moderate inhibitor.
How serious is the interaction between Isoniazid and Lonafarnib?
MediHelp rates it major, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Avoid if possible; if combined, monitor for lonafarnib toxicity including liver tests and blood counts and reduce the dose per labeling.
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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