Drug interactions
Doxylamine + Isocarboxazid
Severity: Major
Doxylamine and Isocarboxazid: 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
Doxylamine is a sedating, strongly anticholinergic antihistamine, and an MAO inhibitor may prolong and intensify these effects. Patients may develop marked drowsiness, urinary retention, constipation, blurred vision and confusion.
What this interaction means in plain words
Doxylamine and Isocarboxazid 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.
Doxylamine belongs to Respiratory; Isocarboxazid belongs to Central Nervous System.
Why it happens
Additive anticholinergic and CNS depressant effects, with MAO inhibition potentially prolonging antihistamine anticholinergic activity.
What to do
Avoid doxylamine-containing sleep or cold products in patients taking isocarboxazid and use a non-sedating alternative. If used, monitor for oversedation and anticholinergic toxicity.
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 Isocarboxazid
- 5-HTP + Isocarboxazid Contraindicated
- Amitriptyline + Isocarboxazid Contraindicated
- Amobarbital + Isocarboxazid Contraindicated
- Amoxapine + Isocarboxazid Contraindicated
- Apraclonidine + Isocarboxazid Contraindicated
- Atomoxetine + Isocarboxazid Contraindicated
Other interactions of Doxylamine
Frequently asked questions
Can I take Doxylamine with Isocarboxazid?
MediHelp rates the interaction as major. Doxylamine and Isocarboxazid 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. Doxylamine is a sedating, strongly anticholinergic antihistamine, and an MAO inhibitor may prolong and intensify these effects. Patients may develop marked drowsiness, urinary retention, constipation, blurred vision and confusion.
How serious is the interaction between Doxylamine and Isocarboxazid?
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 doxylamine-containing sleep or cold products in patients taking isocarboxazid and use a non-sedating alternative. If used, monitor for oversedation and anticholinergic toxicity.
What other medicines interact with Isocarboxazid?
MediHelp also lists interactions of Isocarboxazid with, for example, 5-HTP, Amitriptyline, Amobarbital. The full list is on the Isocarboxazid page.
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