Drug interactions
Codeine + Diazepam
Severity: Major
Codeine and Diazepam: 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
Opioids combined with benzodiazepines cause additive CNS and respiratory depression, with risk of profound sedation, coma and death. This combination carries a regulatory boxed warning.
What this interaction means in plain words
Codeine and Diazepam 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.
Codeine belongs to Musculoskeletal; Diazepam belongs to Musculoskeletal.
Why it happens
Additive CNS and respiratory depression via opioid receptor agonism and GABA-A potentiation.
What to do
Avoid the combination where possible; if it is necessary, use the lowest effective doses for the shortest duration and monitor for sedation and respiratory depression. Counsel patients and caregivers on warning signs.
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
Other interactions of Diazepam
Frequently asked questions
Can I take Codeine with Diazepam?
MediHelp rates the interaction as major. Codeine and Diazepam 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. Opioids combined with benzodiazepines cause additive CNS and respiratory depression, with risk of profound sedation, coma and death. This combination carries a regulatory boxed warning.
How serious is the interaction between Codeine and Diazepam?
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 the combination where possible; if it is necessary, use the lowest effective doses for the shortest duration and monitor for sedation and respiratory depression. Counsel patients and caregivers on warning signs.
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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