Drug interactions
Posaconazole + Promethazine
Severity: Moderate
Posaconazole and Promethazine: 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
Posaconazole can prolong the QT interval and promethazine may add to this effect. Combined use increases the potential for torsades de pointes, particularly with electrolyte disturbances or heart disease.
What this interaction means in plain words
Posaconazole and Promethazine 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.
Posaconazole belongs to Anti Fungals; Promethazine belongs to Respiratory.
Why it happens
Additive QT prolongation.
What to do
Correct potassium and magnesium before use and monitor ECG; consider an alternative antiemetic if QT risk factors are present.
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 Promethazine
- Ibutilide + Promethazine Contraindicated
- Pimozide + Promethazine Contraindicated
- Promethazine + Thioridazine Contraindicated
- Alfentanil + Promethazine Major
- Amiodarone + Promethazine Major
- Amisulpride + Promethazine Major
Other interactions of Posaconazole
- Artemether + Posaconazole Contraindicated
- Avanafil + Posaconazole Contraindicated
- Cobimetinib + Posaconazole Contraindicated
- Conivaptan + Posaconazole Contraindicated
- Dihydroergotamine intranasal + Posaconazole Contraindicated
- Dihydroergotamine + Posaconazole Contraindicated
Frequently asked questions
Can I take Posaconazole with Promethazine?
MediHelp rates the interaction as moderate. Posaconazole and Promethazine 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. Posaconazole can prolong the QT interval and promethazine may add to this effect. Combined use increases the potential for torsades de pointes, particularly with electrolyte disturbances or heart disease.
How serious is the interaction between Posaconazole and Promethazine?
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 monitor ECG; consider an alternative antiemetic if QT risk factors are present.
What other medicines interact with Promethazine?
MediHelp also lists interactions of Promethazine with, for example, Ibutilide, Pimozide, Thioridazine. The full list is on the Promethazine page.
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