Drug interactions
Haloperidol + Sulfamethoxazole
Severity: Moderate
Haloperidol 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
Both agents have been associated with QT prolongation, so combined use may add to the risk of arrhythmia, especially with other risk factors. The risk is mostly relevant in patients with electrolyte disturbance, heart disease or other QT-prolonging drugs.
What this interaction means in plain words
Haloperidol 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
Additive effects on cardiac repolarization; haloperidol blocks hERG channels and sulfamethoxazole-trimethoprim has been linked to QT prolongation.
What to do
Check baseline QTc and electrolytes in at-risk patients and correct potassium and magnesium. 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 Haloperidol
- Dofetilide + Haloperidol Contraindicated
- Dronedarone + Haloperidol Contraindicated
- Haloperidol + Ibutilide Contraindicated
- Haloperidol + Levoketoconazole Contraindicated
- Haloperidol + Panobinostat Contraindicated
- Haloperidol + Pimozide Contraindicated
Frequently asked questions
Can I take Haloperidol with Sulfamethoxazole?
MediHelp rates the interaction as moderate. Haloperidol 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. Both agents have been associated with QT prolongation, so combined use may add to the risk of arrhythmia, especially with other risk factors. The risk is mostly relevant in patients with electrolyte disturbance, heart disease or other QT-prolonging drugs.
How serious is the interaction between Haloperidol 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 baseline QTc and electrolytes in at-risk patients and correct potassium and magnesium. Consider an alternative antibiotic if QTc is prolonged.
What other medicines interact with Haloperidol?
MediHelp also lists interactions of Haloperidol with, for example, Dofetilide, Dronedarone, Ibutilide. The full list is on the Haloperidol page.
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