Drug interactions
Risperidone + Sulfamethoxazole
Severity: Moderate
Risperidone 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 combining them may add to arrhythmia risk, particularly with other risk factors. The clinical risk is generally modest.
What this interaction means in plain words
Risperidone 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 (QT prolongation).
What to do
Check baseline ECG and electrolytes in patients with QT risk factors and correct potassium and magnesium abnormalities; consider an alternative antibiotic if QTc becomes 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 Risperidone
- Ibutilide + Risperidone Contraindicated
- Risperidone + Vandetanib Contraindicated
- Adagrasib + Risperidone Major
- Amiodarone + Risperidone Major
- Amisulpride + Risperidone Major
- Amoxapine + Risperidone Major
Frequently asked questions
Can I take Risperidone with Sulfamethoxazole?
MediHelp rates the interaction as moderate. Risperidone 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 combining them may add to arrhythmia risk, particularly with other risk factors. The clinical risk is generally modest.
How serious is the interaction between Risperidone 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 ECG and electrolytes in patients with QT risk factors and correct potassium and magnesium abnormalities; consider an alternative antibiotic if QTc becomes prolonged.
What other medicines interact with Risperidone?
MediHelp also lists interactions of Risperidone with, for example, Ibutilide, Vandetanib, Adagrasib. The full list is on the Risperidone page.
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