Drug interactions
Promethazine + Voriconazole
Severity: Moderate
Promethazine and Voriconazole: 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 the potential to prolong the QT interval, so their combination may increase the risk of serious ventricular arrhythmias. The concern is greatest with electrolyte abnormalities, heart disease or additional QT-prolonging drugs.
What this interaction means in plain words
Promethazine and Voriconazole 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.
Promethazine belongs to Respiratory; Voriconazole belongs to Anti Fungals.
Why it happens
Additive pharmacodynamic QT prolongation.
What to do
Check baseline ECG and correct hypokalemia and hypomagnesemia. Monitor the QTc during co-therapy and avoid if other QT-prolonging drugs 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 Voriconazole
- Avanafil + Voriconazole Contraindicated
- Butabarbital + Voriconazole Contraindicated
- Carbamazepine + Voriconazole Contraindicated
- Conivaptan + Voriconazole Contraindicated
- Dihydroergotamine intranasal + Voriconazole Contraindicated
- Dihydroergotamine + Voriconazole Contraindicated
Frequently asked questions
Can I take Promethazine with Voriconazole?
MediHelp rates the interaction as moderate. Promethazine and Voriconazole 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 the potential to prolong the QT interval, so their combination may increase the risk of serious ventricular arrhythmias. The concern is greatest with electrolyte abnormalities, heart disease or additional QT-prolonging drugs.
How serious is the interaction between Promethazine and Voriconazole?
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 correct hypokalemia and hypomagnesemia. Monitor the QTc during co-therapy and avoid if other QT-prolonging drugs 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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