Drug interactions
Ethionamide + Isoniazid
Severity: Moderate
Ethionamide and Isoniazid: 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
Both drugs are used together in drug-resistant tuberculosis. They share toxicities, including hepatotoxicity, peripheral and optic neuropathy, and CNS effects, which may be additive.
What this interaction means in plain words
Ethionamide and Isoniazid 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.
Why it happens
Additive pharmacodynamic toxicity; a pharmacokinetic mechanism is not established.
What to do
Monitor liver enzymes and neurological symptoms regularly, and give pyridoxine. Adjust or stop therapy if hepatitis or neuropathy develops.
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
Frequently asked questions
Can I take Ethionamide with Isoniazid?
MediHelp rates the interaction as moderate. Ethionamide and Isoniazid 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. Both drugs are used together in drug-resistant tuberculosis. They share toxicities, including hepatotoxicity, peripheral and optic neuropathy, and CNS effects, which may be additive.
How serious is the interaction between Ethionamide and Isoniazid?
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 neurological symptoms regularly, and give pyridoxine. Adjust or stop therapy if hepatitis or neuropathy develops.
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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