Drug interactions
Isoniazid + Pyridoxine
Severity: Moderate
Isoniazid and Pyridoxine: 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
Isoniazid antagonizes pyridoxine and increases its excretion, which can cause pyridoxine deficiency and peripheral neuropathy. Pyridoxine is routinely given to prevent this, especially in higher-risk patients.
What this interaction means in plain words
Isoniazid and Pyridoxine 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
Isoniazid reacts with pyridoxal phosphate and inhibits pyridoxal kinase, depleting active vitamin B6.
What to do
Give pyridoxine prophylactically, typically 10 to 50 mg daily, in patients at risk of neuropathy, and use higher doses for established neuropathy. Monitor for numbness and paresthesia.
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 Isoniazid with Pyridoxine?
MediHelp rates the interaction as moderate. Isoniazid and Pyridoxine 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 antagonizes pyridoxine and increases its excretion, which can cause pyridoxine deficiency and peripheral neuropathy. Pyridoxine is routinely given to prevent this, especially in higher-risk patients.
How serious is the interaction between Isoniazid and Pyridoxine?
MediHelp rates it moderate, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Give pyridoxine prophylactically, typically 10 to 50 mg daily, in patients at risk of neuropathy, and use higher doses for established neuropathy. Monitor for numbness and paresthesia.
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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