Drug interactions
Diamorphine + Isocarboxazid
Severity: Major
Diamorphine and Isocarboxazid: major interaction.
Last updated Sources: Health Canada product monograph
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
Diamorphine (heroin) with a nonselective MAOI may cause exaggerated opioid effects including respiratory depression and hypotension, and possible serotonin-like toxicity. Severe reactions are described with MAOI-opioid combinations.
What this interaction means in plain words
Diamorphine 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.
Why it happens
MAO inhibition may potentiate opioid and serotonergic effects; the exact mechanism is not fully established.
What to do
Avoid during MAOI therapy and for 14 days after stopping isocarboxazid. If an opioid is essential, use small titrated doses with monitoring of respiration, blood pressure and temperature.
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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References
Other interactions of Isocarboxazid
- 5-HTP + Isocarboxazid Contraindicated
- Amitriptyline + Isocarboxazid Contraindicated
- Amobarbital + Isocarboxazid Contraindicated
- Amoxapine + Isocarboxazid Contraindicated
- Apraclonidine + Isocarboxazid Contraindicated
- Atomoxetine + Isocarboxazid Contraindicated
Frequently asked questions
Can I take Diamorphine with Isocarboxazid?
MediHelp rates the interaction as major. Diamorphine 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. Diamorphine (heroin) with a nonselective MAOI may cause exaggerated opioid effects including respiratory depression and hypotension, and possible serotonin-like toxicity. Severe reactions are described with MAOI-opioid combinations.
How serious is the interaction between Diamorphine 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 during MAOI therapy and for 14 days after stopping isocarboxazid. If an opioid is essential, use small titrated doses with monitoring of respiration, blood pressure and temperature.
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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