Drug interactions
Imipramine + Sulfamethoxazole
Severity: Moderate
Imipramine and Sulfamethoxazole: 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
Imipramine prolongs the QT interval, and sulfamethoxazole (usually given with trimethoprim) has been linked to QT prolongation and arrhythmias in rare reports. The added risk is probably modest but matters in patients with other risk factors.
What this interaction means in plain words
Imipramine and Sulfamethoxazole 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
Possible additive QT prolongation; the mechanism for sulfamethoxazole is not well established.
What to do
Check ECG and electrolytes in patients with cardiac disease, electrolyte abnormalities or other QT-prolonging drugs. Consider an alternative antibiotic if QTc is prolonged.
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 Imipramine
- Dronedarone + Imipramine Contraindicated
- Imipramine + Isocarboxazid Contraindicated
- Imipramine + Phenelzine Contraindicated
- Imipramine + Pimozide Contraindicated
- Imipramine + Rasagiline Contraindicated
- Imipramine + Safinamide Contraindicated
Frequently asked questions
Can I take Imipramine with Sulfamethoxazole?
MediHelp rates the interaction as moderate. Imipramine and Sulfamethoxazole 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. Imipramine prolongs the QT interval, and sulfamethoxazole (usually given with trimethoprim) has been linked to QT prolongation and arrhythmias in rare reports. The added risk is probably modest but matters in patients with other risk factors.
How serious is the interaction between Imipramine and Sulfamethoxazole?
MediHelp rates it moderate, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Check ECG and electrolytes in patients with cardiac disease, electrolyte abnormalities or other QT-prolonging drugs. Consider an alternative antibiotic if QTc is prolonged.
What other medicines interact with Imipramine?
MediHelp also lists interactions of Imipramine with, for example, Dronedarone, Isocarboxazid, Phenelzine. The full list is on the Imipramine page.
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