Drug interactions
Glycopyrronium + Promethazine
Severity: Moderate
Glycopyrronium 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
Promethazine is a strongly anticholinergic antihistamine, and combining it with glycopyrronium can intensify dry mouth, constipation, urinary retention, blurred vision and tachycardia. Sedation and confusion may also be more pronounced in older adults.
What this interaction means in plain words
Glycopyrronium 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.
Glycopyrronium belongs to Respiratory; Promethazine belongs to Respiratory.
Why it happens
Additive antimuscarinic effects at peripheral and central receptors.
What to do
Monitor for anticholinergic toxicity, especially in the elderly, and reduce doses or choose a less anticholinergic antihistamine if needed.
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 Glycopyrronium
- Clozapine + Glycopyrronium Major
- Abobotulinumtoxina + Glycopyrronium Moderate
- Aclidinium + Glycopyrronium Moderate
- Amantadine + Glycopyrronium Moderate
- Amitriptyline + Glycopyrronium Moderate
- Amoxapine + Glycopyrronium Moderate
Other interactions of Promethazine
- Ibutilide + Promethazine Contraindicated
- Pimozide + Promethazine Contraindicated
- Promethazine + Thioridazine Contraindicated
- Alfentanil + Promethazine Major
- Amiodarone + Promethazine Major
- Amisulpride + Promethazine Major
Frequently asked questions
Can I take Glycopyrronium with Promethazine?
MediHelp rates the interaction as moderate. Glycopyrronium 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. Promethazine is a strongly anticholinergic antihistamine, and combining it with glycopyrronium can intensify dry mouth, constipation, urinary retention, blurred vision and tachycardia. Sedation and confusion may also be more pronounced in older adults.
How serious is the interaction between Glycopyrronium 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: Monitor for anticholinergic toxicity, especially in the elderly, and reduce doses or choose a less anticholinergic antihistamine if needed.
What other medicines interact with Glycopyrronium?
MediHelp also lists interactions of Glycopyrronium with, for example, Clozapine, Abobotulinumtoxina, Aclidinium. The full list is on the Glycopyrronium page.
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