Drug interactions
Clozapine + Diamorphine
Severity: Major
Clozapine and Diamorphine: major interaction.
Last updated Sources: UK SmPC
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 and clozapine both depress the CNS, and the combination can cause deep sedation, hypotension and respiratory depression. Cases of circulatory collapse have been described with clozapine and CNS depressants.
What this interaction means in plain words
Clozapine and Diamorphine 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
Additive CNS and respiratory depression from opioid agonism and clozapine sedation.
What to do
Use reduced initial opioid doses and monitor respiratory rate, sedation and blood pressure closely. Avoid adding other sedatives.
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 Clozapine
- Clozapine + Deferiprone Contraindicated
- Clozapine + Irinotecan Contraindicated
- Clozapine + Pimozide Contraindicated
- Clozapine + Thioridazine Contraindicated
- Acalabrutinib + Clozapine Major
- Adagrasib + Clozapine Major
Frequently asked questions
Can I take Clozapine with Diamorphine?
MediHelp rates the interaction as major. Clozapine and Diamorphine 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 and clozapine both depress the CNS, and the combination can cause deep sedation, hypotension and respiratory depression. Cases of circulatory collapse have been described with clozapine and CNS depressants.
How serious is the interaction between Clozapine and Diamorphine?
MediHelp rates it major, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Use reduced initial opioid doses and monitor respiratory rate, sedation and blood pressure closely. Avoid adding other sedatives.
What other medicines interact with Clozapine?
MediHelp also lists interactions of Clozapine with, for example, Deferiprone, Irinotecan, Pimozide. The full list is on the Clozapine page.
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