Drug interactions
Diphenhydramine + Tiotropium-olodaterol
Severity: Minor
Diphenhydramine and Tiotropium-olodaterol: minor 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
Diphenhydramine has pronounced anticholinergic effects that add to tiotropium, increasing dry mouth, urinary retention, constipation, confusion and blurred vision, particularly in older adults. Systemic tiotropium exposure is low, so the effect is generally mild.
What this interaction means in plain words
Diphenhydramine and Tiotropium-olodaterol have a small, usually unimportant interaction. Most people can take both; the pharmacist may still mention it so that any unexpected effect is recognised.
Diphenhydramine belongs to Respiratory; Tiotropium-olodaterol belongs to Respiratory.
Why it happens
Additive antimuscarinic effects.
What to do
Monitor older patients for anticholinergic adverse effects and prefer a non-sedating antihistamine where suitable.
What to ask your pharmacist
- Is there anything I should notice while taking both?
- Do I need to tell my doctor at the next visit?
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Other interactions of Tiotropium-olodaterol
Other interactions of Diphenhydramine
Frequently asked questions
Can I take Diphenhydramine with Tiotropium-olodaterol?
MediHelp rates the interaction as minor. Diphenhydramine and Tiotropium-olodaterol have a small, usually unimportant interaction. Most people can take both; the pharmacist may still mention it so that any unexpected effect is recognised. Diphenhydramine has pronounced anticholinergic effects that add to tiotropium, increasing dry mouth, urinary retention, constipation, confusion and blurred vision, particularly in older adults. Systemic tiotropium exposure is low, so the effect is generally mild.
How serious is the interaction between Diphenhydramine and Tiotropium-olodaterol?
MediHelp rates it minor, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Monitor older patients for anticholinergic adverse effects and prefer a non-sedating antihistamine where suitable.
What other medicines interact with Tiotropium-olodaterol?
MediHelp also lists interactions of Tiotropium-olodaterol with, for example, Amisulpride, Arformoterol, Arsenic trioxide. The full list is on the Tiotropium-olodaterol page.
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