Drug interactions
Orphenadrin + Physostigmine
Severity: Moderate
Orphenadrin and Physostigmine: 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 acetylcholinesterase, which directly opposes the antimuscarinic action of orphenadrine. This is the basis for using physostigmine in anticholinergic toxicity, but it can also reduce the intended effect of orphenadrine.
What this interaction means in plain words
Orphenadrin 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 a cholinesterase inhibitor and an antimuscarinic agent.
What to do
Monitor for reduced effect of either drug. When physostigmine is used for orphenadrine overdose, watch for bradycardia, seizures and cholinergic excess.
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 Orphenadrin
Frequently asked questions
Can I take Orphenadrin with Physostigmine?
MediHelp rates the interaction as moderate. Orphenadrin 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 inhibits acetylcholinesterase, which directly opposes the antimuscarinic action of orphenadrine. This is the basis for using physostigmine in anticholinergic toxicity, but it can also reduce the intended effect of orphenadrine.
How serious is the interaction between Orphenadrin 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: Monitor for reduced effect of either drug. When physostigmine is used for orphenadrine overdose, watch for bradycardia, seizures and cholinergic excess.
What other medicines interact with Orphenadrin?
MediHelp also lists interactions of Orphenadrin with, for example, Alfentanil, Amobarbital, Benzhydrocodone / acetaminophen. The full list is on the Orphenadrin page.
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