Drug interactions
Chlorpheniramine + Isocarboxazid
Severity: Major
Chlorpheniramine 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
Chlorpheniramine has serotonin reuptake inhibiting properties in addition to anticholinergic and sedative effects, so combining it with an MAO inhibitor adds a theoretical serotonergic risk. Increased sedation and anticholinergic effects are more likely.
What this interaction means in plain words
Chlorpheniramine 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.
Chlorpheniramine belongs to Respiratory; Isocarboxazid belongs to Central Nervous System.
Why it happens
Additive CNS depression and anticholinergic effects, plus weak serotonin reuptake inhibition by chlorpheniramine on top of MAO inhibition.
What to do
Avoid chlorpheniramine and choose a non-sedating antihistamine. If it cannot be avoided, use low doses and monitor for sedation, anticholinergic effects and serotonin 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 Chlorpheniramine
Frequently asked questions
Can I take Chlorpheniramine with Isocarboxazid?
MediHelp rates the interaction as major. Chlorpheniramine 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. Chlorpheniramine has serotonin reuptake inhibiting properties in addition to anticholinergic and sedative effects, so combining it with an MAO inhibitor adds a theoretical serotonergic risk. Increased sedation and anticholinergic effects are more likely.
How serious is the interaction between Chlorpheniramine 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 chlorpheniramine and choose a non-sedating antihistamine. If it cannot be avoided, use low doses and monitor for sedation, anticholinergic effects and serotonin 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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