Drug interactions
Diphenoxylate-atropine + Physostigmine
Severity: Moderate
Diphenoxylate-atropine and Physostigmine: moderate interaction.
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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 is a cholinesterase inhibitor that opposes the anticholinergic effects of atropine, which is present in the combination product. The effects partly cancel each other, so the antidiarrheal and anticholinergic actions of atropine may be reduced. This is the basis for physostigmine use in anticholinergic toxicity.
What this interaction means in plain words
Diphenoxylate-atropine and Physostigmine 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 muscarinic blockade by atropine and increased acetylcholine from cholinesterase inhibition.
What to do
Avoid using together unless physostigmine is being given to treat anticholinergic toxicity; monitor heart rate, bowel activity and secretions. Watch for cholinergic effects such as bradycardia if atropine effect wanes.
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 Diphenoxylate-atropine
- Diphenoxylate-atropine + Isocarboxazid Contraindicated
- Diphenoxylate-atropine + Phenelzine Contraindicated
- Diphenoxylate-atropine + Tranylcypromine Contraindicated
- Alfentanil + Diphenoxylate-atropine Major
- Alvimopan + Diphenoxylate-atropine Major
- Amitriptyline + Diphenoxylate-atropine Major
Frequently asked questions
Can I take Diphenoxylate-atropine with Physostigmine?
MediHelp rates the interaction as moderate. Diphenoxylate-atropine and Physostigmine 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 is a cholinesterase inhibitor that opposes the anticholinergic effects of atropine, which is present in the combination product. The effects partly cancel each other, so the antidiarrheal and anticholinergic actions of atropine may be reduced. This is the basis for physostigmine use in anticholinergic toxicity.
How serious is the interaction between Diphenoxylate-atropine and Physostigmine?
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 using together unless physostigmine is being given to treat anticholinergic toxicity; monitor heart rate, bowel activity and secretions. Watch for cholinergic effects such as bradycardia if atropine effect wanes.
What other medicines interact with Diphenoxylate-atropine?
MediHelp also lists interactions of Diphenoxylate-atropine with, for example, Isocarboxazid, Phenelzine, Tranylcypromine. The full list is on the Diphenoxylate-atropine page.
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