Drug interactions
Physostigmine + Trospium
Severity: Moderate
Physostigmine and Trospium: 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
Physostigmine inhibits cholinesterase and increases cholinergic activity, which directly opposes trospium's muscarinic blockade. Physostigmine can reverse the anticholinergic effects of trospium, which is the basis for its use in anticholinergic toxicity.
What this interaction means in plain words
Physostigmine and Trospium 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.
Why it happens
Pharmacodynamic antagonism between a cholinesterase inhibitor and a muscarinic antagonist.
What to do
Expect reduced trospium effect when both are given; in anticholinergic toxicity, give physostigmine under monitoring for bradycardia, seizures and cholinergic effects.
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 Trospium
- Clozapine + Trospium Major
- Pramlintide + Trospium Major
- Thioridazine + Trospium Major
- Trihexyphenidyl + Trospium Major
- Aclidinium + Trospium Moderate
- Amantadine + Trospium Moderate
Frequently asked questions
Can I take Physostigmine with Trospium?
MediHelp rates the interaction as moderate. Physostigmine and Trospium 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. Physostigmine inhibits cholinesterase and increases cholinergic activity, which directly opposes trospium's muscarinic blockade. Physostigmine can reverse the anticholinergic effects of trospium, which is the basis for its use in anticholinergic toxicity.
How serious is the interaction between Physostigmine and Trospium?
MediHelp rates it moderate, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Expect reduced trospium effect when both are given; in anticholinergic toxicity, give physostigmine under monitoring for bradycardia, seizures and cholinergic effects.
What other medicines interact with Trospium?
MediHelp also lists interactions of Trospium with, for example, Clozapine, Pramlintide, Thioridazine. The full list is on the Trospium page.
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