Drug interactions
Promethazine + Solifenacin
Severity: Moderate
Promethazine and Solifenacin: 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 drugs are antimuscarinic, so combining them increases dry mouth, constipation, urinary retention, blurred vision and confusion, particularly in older adults. Both also may affect the QT interval.
What this interaction means in plain words
Promethazine and Solifenacin 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; Solifenacin belongs to Genitourinary.
Why it happens
Additive muscarinic receptor antagonism.
What to do
Monitor for anticholinergic effects and cognitive changes, and avoid the combination in frail elderly patients where possible. Consider an alternative antiemetic or antihistamine.
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 Solifenacin
Frequently asked questions
Can I take Promethazine with Solifenacin?
MediHelp rates the interaction as moderate. Promethazine and Solifenacin 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 drugs are antimuscarinic, so combining them increases dry mouth, constipation, urinary retention, blurred vision and confusion, particularly in older adults. Both also may affect the QT interval.
How serious is the interaction between Promethazine and Solifenacin?
MediHelp rates it moderate, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Monitor for anticholinergic effects and cognitive changes, and avoid the combination in frail elderly patients where possible. Consider an alternative antiemetic or antihistamine.
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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