Drug interactions
Dimenhydrinate + Tolterodine
Severity: Moderate
Dimenhydrinate and Tolterodine: 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
Dimenhydrinate contains diphenhydramine, a first-generation antihistamine with strong antimuscarinic activity. Taken with tolterodine it can add to dry mouth, constipation, urinary retention, blurred vision and confusion, particularly in older adults.
What this interaction means in plain words
Dimenhydrinate and Tolterodine 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.
Dimenhydrinate belongs to Respiratory; Tolterodine belongs to Genitourinary.
Why it happens
Additive antimuscarinic (anticholinergic) pharmacodynamic effects.
What to do
Avoid routine combination in older or cognitively vulnerable patients and choose a non-anticholinergic antiemetic or antihistamine. If used together, monitor for urinary retention, constipation and confusion.
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 Tolterodine
Other interactions of Dimenhydrinate
Frequently asked questions
Can I take Dimenhydrinate with Tolterodine?
MediHelp rates the interaction as moderate. Dimenhydrinate and Tolterodine 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. Dimenhydrinate contains diphenhydramine, a first-generation antihistamine with strong antimuscarinic activity. Taken with tolterodine it can add to dry mouth, constipation, urinary retention, blurred vision and confusion, particularly in older adults.
How serious is the interaction between Dimenhydrinate and Tolterodine?
MediHelp rates it moderate, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Avoid routine combination in older or cognitively vulnerable patients and choose a non-anticholinergic antiemetic or antihistamine. If used together, monitor for urinary retention, constipation and confusion.
What other medicines interact with Tolterodine?
MediHelp also lists interactions of Tolterodine with, for example, Clarithromycin, Clozapine, Cobicistat. The full list is on the Tolterodine page.
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