Drug interactions
Sulfamethoxazole + Trazodone
Severity: Moderate
Sulfamethoxazole and Trazodone: 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
Trazodone can prolong the QT interval, and sulfamethoxazole-trimethoprim has been linked to QT prolongation and hyperkalemia in some patients. Combined use may increase the risk of arrhythmia, particularly with electrolyte disturbance or cardiac disease.
What this interaction means in plain words
Sulfamethoxazole and Trazodone 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 QT prolongation, with electrolyte effects possibly contributing.
What to do
Check ECG and electrolytes in patients with QT risk factors, and correct potassium and magnesium abnormalities.
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 Trazodone
- Arsenic trioxide + Trazodone Contraindicated
- Ibutilide + Trazodone Contraindicated
- Isocarboxazid + Trazodone Contraindicated
- Levoketoconazole + Trazodone Contraindicated
- Methylene blue + Trazodone Contraindicated
- Phenelzine + Trazodone Contraindicated
Frequently asked questions
Can I take Sulfamethoxazole with Trazodone?
MediHelp rates the interaction as moderate. Sulfamethoxazole and Trazodone 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. Trazodone can prolong the QT interval, and sulfamethoxazole-trimethoprim has been linked to QT prolongation and hyperkalemia in some patients. Combined use may increase the risk of arrhythmia, particularly with electrolyte disturbance or cardiac disease.
How serious is the interaction between Sulfamethoxazole and Trazodone?
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 QT risk factors, and correct potassium and magnesium abnormalities.
What other medicines interact with Trazodone?
MediHelp also lists interactions of Trazodone with, for example, Arsenic trioxide, Ibutilide, Isocarboxazid. The full list is on the Trazodone page.
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