Drug interactions
Hyoscyamine + Tiotropium
Severity: Moderate
Hyoscyamine 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
Both drugs are antimuscarinic, so combining them adds to anticholinergic effects. This can cause dry mouth, constipation, urinary retention, blurred vision, tachycardia and confusion, especially in older adults. Narrow-angle glaucoma or prostatic hypertrophy may worsen.
What this interaction means in plain words
Hyoscyamine 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.
Hyoscyamine belongs to Genitourinary; Tiotropium belongs to Respiratory.
Why it happens
Additive antagonism at muscarinic receptors, with some systemic absorption of inhaled tiotropium.
What to do
Avoid duplicate antimuscarinic therapy where possible. If both are needed, monitor for urinary retention, constipation, ocular symptoms and cognitive effects, and reduce the hyoscyamine dose if adverse effects appear.
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?
Pro+ members
Unlock the full page
Create an account and start a Pro+ trial to unlock the full management advice for Hyoscyamine and Tiotropium, the additional notes, the evidence detail and the whole-prescription interaction checker.
- Full clinical management advice
- Additional notes
- Evidence detail
- Interaction checker for a whole prescription
Try Pro+ free for 7 days on the web. No card needed.
Other interactions of Tiotropium
Other interactions of Hyoscyamine
- Amantadine + Hyoscyamine Moderate
- Amitriptyline + Hyoscyamine Moderate
- Aripiprazole + Hyoscyamine Moderate
- Atropine + Hyoscyamine Moderate
- Benztropine + Hyoscyamine Moderate
- Bethanechol + Hyoscyamine Moderate
Frequently asked questions
Can I take Hyoscyamine with Tiotropium?
MediHelp rates the interaction as moderate. Hyoscyamine 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. Both drugs are antimuscarinic, so combining them adds to anticholinergic effects. This can cause dry mouth, constipation, urinary retention, blurred vision, tachycardia and confusion, especially in older adults. Narrow-angle glaucoma or prostatic hypertrophy may worsen.
How serious is the interaction between Hyoscyamine 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: Avoid duplicate antimuscarinic therapy where possible. If both are needed, monitor for urinary retention, constipation, ocular symptoms and cognitive effects, and reduce the hyoscyamine dose if adverse effects appear.
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.
Full monographs, dosing and an interaction checker in the MediHelp app
Open the complete reference, check multi-drug interactions and use dosing tools in the MediHelp app.
