Trospium and Metformin Interaction
Drug interaction information between Trospium and Metformin.
Trospium and Metformin have a documented minor interaction in FDA labeling.
FDA drug labeling documents a minor-severity interaction between Trospium and Metformin. Major interactions are generally avoided, moderate ones may need monitoring or a dose adjustment, and minor ones are usually low-risk. This page shows the documented mechanism and guidance. Label-documented interactions are not a complete safety review, so always confirm your own medications with a pharmacist or doctor. Educational information, not medical advice.
How They Interact
Metformin lowers the amount of trospium that gets into your bloodstream. This means there is less medicine available in your body to do its job.
What To Do
Your doctor may need to change your dose of trospium to make sure it still works for you.
FDA Label Information
( 7.2 ) Concomitant use with metformin immediate release tablets reduced exposure and peak concentration of trospium. 7.4 Metformin Co-administration of 500 mg metformin immediate release tablets twice daily with trospium chloride 60 mg extended release reduced the steady-state systemic exposure of trospium by approximately 29% for mean AUC 0-24 and by 34% for mean C max [ see Clinical Pharmacology (12.3) ].
Trospium Also Interacts With
- Morphine minor
- Vancomycin minor
- Digoxin minor
Metformin Also Interacts With
- Bictegravir/Emtricitabine/Tenofovir moderate
- Dolutegravir/Lamivudine moderate
- Empagliflozin moderate
- Empagliflozin/Linagliptin moderate
- Ertugliflozin moderate
Frequently Asked Questions
Can I take Trospium and Metformin together?
This is a minor interaction. Your doctor may need to change your dose of trospium to make sure it still works for you.
How serious is the interaction between Trospium and Metformin?
This interaction is classified as "minor" severity by the FDA. Minor interactions are unlikely to cause significant problems but should still be mentioned to your healthcare provider.
Why do Trospium and Metformin interact?
Metformin lowers the amount of trospium that gets into your bloodstream. This means there is less medicine available in your body to do its job.
Understanding the Trospium and Metformin Interaction
FDA-approved prescribing information for these two drugs flags their combination as a minor-severity interaction. Trospium belongs to the Anticholinergic (Overactive Bladder) class and Metformin belongs to the Biguanide class - two categories that can collide when co-prescribed. The mechanism described in FDA labeling is: Metformin lowers the amount of trospium that gets into your bloodstream. Severity tiers matter: major flags generally advise avoidance, moderate flags often require monitoring or dose adjustment, and minor flags may only call for awareness.
Context around a specific patient determines real-world impact. Trospium has 4 total documented interactions on file in this dataset, and Metformin has 27. Each additional medication compounds the interaction surface, which is why pharmacists run full-profile checks rather than evaluating one pair at a time. FDA-derived guidance for this pair is: Your doctor may need to change your dose of trospium to make sure it still works for you. Timing of doses, renal and hepatic function, age, and other concurrent prescriptions all shape whether a labeled interaction matters clinically.
An interaction flag is not a verdict. A large share of labeled interactions are managed routinely in clinical practice, the fix may be as simple as spacing doses or adding a monitoring test. Others require the prescriber to choose a different medication entirely. This page surfaces FDA-sourced labeling and openFDA data for educational purposes only; it is not medical advice and cannot account for your full clinical picture. Never start, stop, or adjust either Trospium or Metformin based on a web page, speak with your prescriber or pharmacist before making any change.
Sources: FDA Drug Labels (SPL) via openFDA (2026). This is for informational purposes only and is not medical advice. Always consult your healthcare provider about drug interactions.
Read our methodology - how this data is sourced, computed, and verified.