Drug interactions
Dolasetron + Sulfamethoxazole
Severity: Moderate
Dolasetron 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
Dolasetron's active metabolite hydrodolasetron prolongs the PR, QRS and QT intervals in a dose-related way. Sulfamethoxazole (usually given with trimethoprim) has been linked to rare QT prolongation and torsades reports. Giving both may add to arrhythmia risk, particularly with electrolyte disturbance or cardiac disease.
What this interaction means in plain words
Dolasetron 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 prolongation of ventricular repolarization; the evidence for sulfamethoxazole's QT effect is weak.
What to do
Correct potassium and magnesium before use and consider an ECG in patients with cardiac disease or other QT-prolonging drugs. Consider an alternative antiemetic such as a 5-HT3 antagonist with less cardiac effect, or an alternative antibiotic, in high-risk patients.
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 Dolasetron
- Apomorphine + Dolasetron Contraindicated
- Dofetilide + Dolasetron Contraindicated
- Dolasetron + Ibutilide Contraindicated
- Dolasetron + Pimozide Contraindicated
- Dolasetron + Thioridazine Contraindicated
- Dolasetron + Vandetanib Contraindicated
Frequently asked questions
Can I take Dolasetron with Sulfamethoxazole?
MediHelp rates the interaction as moderate. Dolasetron 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. Dolasetron's active metabolite hydrodolasetron prolongs the PR, QRS and QT intervals in a dose-related way. Sulfamethoxazole (usually given with trimethoprim) has been linked to rare QT prolongation and torsades reports. Giving both may add to arrhythmia risk, particularly with electrolyte disturbance or cardiac disease.
How serious is the interaction between Dolasetron 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: Correct potassium and magnesium before use and consider an ECG in patients with cardiac disease or other QT-prolonging drugs. Consider an alternative antiemetic such as a 5-HT3 antagonist with less cardiac effect, or an alternative antibiotic, in high-risk patients.
What other medicines interact with Dolasetron?
MediHelp also lists interactions of Dolasetron with, for example, Apomorphine, Dofetilide, Ibutilide. The full list is on the Dolasetron page.
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