Drug interactions
Disopyramide + Isoniazid
Severity: Moderate
Disopyramide 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
Isoniazid may modestly raise disopyramide concentrations because it inhibits CYP3A4, the main pathway for disopyramide's conversion to its less active metabolite. Higher exposure could increase anticholinergic effects, hypotension and QT prolongation. The effect of isoniazid on this enzyme is variable and generally weak.
What this interaction means in plain words
Disopyramide 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.
Disopyramide belongs to Cardiovascular; Isoniazid belongs to Anti Bacterial.
Why it happens
Isoniazid inhibits CYP3A4, reducing the metabolism of disopyramide.
What to do
Monitor ECG (QT/QRS interval), blood pressure and anticholinergic symptoms when starting or stopping isoniazid. Reduce the disopyramide dose if signs of toxicity appear.
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 Disopyramide
- Amisulpride + Disopyramide Contraindicated
- Desipramine + Disopyramide Contraindicated
- Disopyramide + Dronedarone Contraindicated
- Disopyramide + Itraconazole Contraindicated
- Disopyramide + Ketoconazole Contraindicated
- Disopyramide + Maprotiline Contraindicated
Frequently asked questions
Can I take Disopyramide with Isoniazid?
MediHelp rates the interaction as moderate. Disopyramide 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. Isoniazid may modestly raise disopyramide concentrations because it inhibits CYP3A4, the main pathway for disopyramide's conversion to its less active metabolite. Higher exposure could increase anticholinergic effects, hypotension and QT prolongation. The effect of isoniazid on this enzyme is variable and generally weak.
How serious is the interaction between Disopyramide 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 ECG (QT/QRS interval), blood pressure and anticholinergic symptoms when starting or stopping isoniazid. Reduce the disopyramide dose if signs of toxicity appear.
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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