Drug interactions
Codeine + Diamorphine
Severity: Major
Codeine and Diamorphine: major interaction.
Last updated Sources: US FDA label
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
Combining two opioid agonists adds to central nervous system and respiratory depression. Sedation, hypotension and breathing suppression can occur, particularly in opioid-naive or frail patients.
What this interaction means in plain words
Codeine 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 mu-opioid receptor agonism causing pharmacodynamic CNS and respiratory depression.
What to do
Avoid routine duplication of opioids; if both are needed, use the lowest effective doses and monitor sedation level and respiratory rate. Reduce the dose of one agent when titrating.
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 Codeine
- Alvimopan + Codeine Contraindicated
- Codeine + Isocarboxazid Contraindicated
- Codeine + Olanzapine / samidorphan Contraindicated
- Codeine + Phenelzine Contraindicated
- Codeine + Tranylcypromine Contraindicated
- Alfentanil + Codeine Major
Frequently asked questions
Can I take Codeine with Diamorphine?
MediHelp rates the interaction as major. Codeine 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. Combining two opioid agonists adds to central nervous system and respiratory depression. Sedation, hypotension and breathing suppression can occur, particularly in opioid-naive or frail patients.
How serious is the interaction between Codeine 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: Avoid routine duplication of opioids; if both are needed, use the lowest effective doses and monitor sedation level and respiratory rate. Reduce the dose of one agent when titrating.
What other medicines interact with Codeine?
MediHelp also lists interactions of Codeine with, for example, Alvimopan, Isocarboxazid, Olanzapine / samidorphan. The full list is on the Codeine page.
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