Drug interactions
Citalopram + Isoniazid
Severity: Moderate
Citalopram 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 inhibit CYP2C19 and increase citalopram levels, which adds to the dose-dependent risk of QT prolongation. Citalopram labeling limits the dose in patients receiving CYP2C19 inhibitors.
What this interaction means in plain words
Citalopram 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.
Citalopram belongs to Central Nervous System; Isoniazid belongs to Anti Bacterial.
Why it happens
Inhibition of CYP2C19 (and CYP3A4) by isoniazid reduces citalopram metabolism.
What to do
Keep citalopram at or below the labeled maximum for CYP2C19 inhibitors, which is 20 mg daily. Consider an ECG and electrolyte check if other QT risk factors are present.
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 Citalopram
- Cisapride + Citalopram Contraindicated
- Citalopram + Dronedarone Contraindicated
- Citalopram + Escitalopram Contraindicated
- Citalopram + Isocarboxazid Contraindicated
- Citalopram + Methylene blue Contraindicated
- Citalopram + Phenelzine Contraindicated
Frequently asked questions
Can I take Citalopram with Isoniazid?
MediHelp rates the interaction as moderate. Citalopram 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 inhibit CYP2C19 and increase citalopram levels, which adds to the dose-dependent risk of QT prolongation. Citalopram labeling limits the dose in patients receiving CYP2C19 inhibitors.
How serious is the interaction between Citalopram 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: Keep citalopram at or below the labeled maximum for CYP2C19 inhibitors, which is 20 mg daily. Consider an ECG and electrolyte check if other QT risk factors are present.
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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