Drug interactions
Diphenhydramine + Glycopyrrolate inhaled
Severity: Moderate
Diphenhydramine and Glycopyrrolate inhaled: 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
Inhaled glycopyrrolate has some systemic absorption, and with oral diphenhydramine anticholinergic effects such as dry mouth, constipation and urinary retention can add up. The effect is generally modest at usual doses.
What this interaction means in plain words
Diphenhydramine and Glycopyrrolate inhaled 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
Additive antimuscarinic receptor blockade.
What to do
Monitor for urinary retention, constipation and dry mouth. Avoid in patients with narrow-angle glaucoma or bladder outlet obstruction.
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 Diphenhydramine
Frequently asked questions
Can I take Diphenhydramine with Glycopyrrolate inhaled?
MediHelp rates the interaction as moderate. Diphenhydramine and Glycopyrrolate inhaled 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. Inhaled glycopyrrolate has some systemic absorption, and with oral diphenhydramine anticholinergic effects such as dry mouth, constipation and urinary retention can add up. The effect is generally modest at usual doses.
How serious is the interaction between Diphenhydramine and Glycopyrrolate inhaled?
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 urinary retention, constipation and dry mouth. Avoid in patients with narrow-angle glaucoma or bladder outlet obstruction.
What other medicines interact with Diphenhydramine?
MediHelp also lists interactions of Diphenhydramine with, for example, Alfentanil, Belladonna and opium, Benzhydrocodone / acetaminophen. The full list is on the Diphenhydramine page.
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