Drug interactions
Meclizine + Physostigmine
Severity: Moderate
Meclizine 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 and can reverse central and peripheral anticholinergic effects, which opposes meclizine's antimuscarinic activity. This is the basis for its use in anticholinergic toxicity, so meclizine's effect may be reduced while physostigmine's cholinergic side effects remain.
What this interaction means in plain words
Meclizine 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 cholinesterase inhibition and muscarinic/H1 blockade.
What to do
If used intentionally to treat anticholinergic toxicity, give physostigmine under monitored conditions with atropine available. Otherwise avoid combining them and watch for bradycardia, seizures and bronchorrhea.
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 Meclizine
Frequently asked questions
Can I take Meclizine with Physostigmine?
MediHelp rates the interaction as moderate. Meclizine 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 and can reverse central and peripheral anticholinergic effects, which opposes meclizine's antimuscarinic activity. This is the basis for its use in anticholinergic toxicity, so meclizine's effect may be reduced while physostigmine's cholinergic side effects remain.
How serious is the interaction between Meclizine 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: If used intentionally to treat anticholinergic toxicity, give physostigmine under monitored conditions with atropine available. Otherwise avoid combining them and watch for bradycardia, seizures and bronchorrhea.
What other medicines interact with Meclizine?
MediHelp also lists interactions of Meclizine with, for example, Belladonna and opium, Benzhydrocodone / acetaminophen, Brexanolone. The full list is on the Meclizine page.
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