Drug interactions
Amitriptyline + Physostigmine
Severity: Major
Amitriptyline and Physostigmine: major 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 is a cholinesterase inhibitor that is used to reverse anticholinergic toxicity. In tricyclic overdose it is not recommended because it can precipitate seizures, bradycardia and asystole. At therapeutic doses the antimuscarinic effect of amitriptyline can oppose physostigmine.
What this interaction means in plain words
Amitriptyline and Physostigmine can interact in a way that may be serious. Using them together is sometimes necessary, but it needs a deliberate decision by the prescriber, a plan for monitoring, and clear advice on the warning signs to watch for.
Why it happens
Pharmacodynamic opposition at muscarinic receptors, with cholinergic excess in tricyclic toxicity promoting seizures and conduction disturbances.
What to do
Avoid physostigmine for tricyclic antidepressant overdose and use supportive care and standard measures such as sodium bicarbonate for conduction abnormalities. If physostigmine is used for another indication, monitor ECG and seizure activity.
What to ask your pharmacist
- Does the benefit of taking both outweigh the risk in my case?
- Do I need any blood test, ECG or other check while on both?
- What early warning signs should I watch for, and what should I do if they appear?
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Other interactions of Amitriptyline
- Amitriptyline + Isocarboxazid Contraindicated
- Amitriptyline + Methylene blue Contraindicated
- Amitriptyline + Phenelzine Contraindicated
- Amitriptyline + Pimozide Contraindicated
- Amitriptyline + Procarbazine Contraindicated
- Amitriptyline + Safinamide Contraindicated
Frequently asked questions
Can I take Amitriptyline with Physostigmine?
MediHelp rates the interaction as major. Amitriptyline and Physostigmine can interact in a way that may be serious. Using them together is sometimes necessary, but it needs a deliberate decision by the prescriber, a plan for monitoring, and clear advice on the warning signs to watch for. Physostigmine is a cholinesterase inhibitor that is used to reverse anticholinergic toxicity. In tricyclic overdose it is not recommended because it can precipitate seizures, bradycardia and asystole. At therapeutic doses the antimuscarinic effect of amitriptyline can oppose physostigmine.
How serious is the interaction between Amitriptyline and Physostigmine?
MediHelp rates it major, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Avoid physostigmine for tricyclic antidepressant overdose and use supportive care and standard measures such as sodium bicarbonate for conduction abnormalities. If physostigmine is used for another indication, monitor ECG and seizure activity.
What other medicines interact with Amitriptyline?
MediHelp also lists interactions of Amitriptyline with, for example, Isocarboxazid, Methylene blue, Phenelzine. The full list is on the Amitriptyline page.
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