Drug interactions
Homatropine + Tiotropium
Severity: Moderate
Homatropine and Tiotropium: 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
Homatropine is an antimuscarinic and can add to the anticholinergic effects of tiotropium. Systemic effects are more likely with oral combination cough products than with eye drops.
What this interaction means in plain words
Homatropine and Tiotropium 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.
Homatropine belongs to Genitourinary; Tiotropium belongs to Respiratory.
Why it happens
Additive muscarinic receptor antagonism.
What to do
Monitor for dry mouth, urinary retention, constipation and tachycardia. Avoid in narrow-angle glaucoma.
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 Tiotropium
Other interactions of Homatropine
- Amantadine + Homatropine Moderate
- Amitriptyline + Homatropine Moderate
- Atropine + Homatropine Moderate
- Benztropine + Homatropine Moderate
- Bethanechol + Homatropine Moderate
- Chlorpromazine + Homatropine Moderate
Frequently asked questions
Can I take Homatropine with Tiotropium?
MediHelp rates the interaction as moderate. Homatropine and Tiotropium 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. Homatropine is an antimuscarinic and can add to the anticholinergic effects of tiotropium. Systemic effects are more likely with oral combination cough products than with eye drops.
How serious is the interaction between Homatropine and Tiotropium?
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 dry mouth, urinary retention, constipation and tachycardia. Avoid in narrow-angle glaucoma.
What other medicines interact with Tiotropium?
MediHelp also lists interactions of Tiotropium with, for example, Glycopyrrolate inhaled, Indacaterol-glycopyrronium, Revefenacin. The full list is on the Tiotropium page.
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