Drug interactions
Codeine + Olanzapine / samidorphan
Severity: Contraindicated
Codeine and Olanzapine / samidorphan: contraindicated 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
Samidorphan blocks opioid receptors, reducing codeine analgesia and potentially precipitating withdrawal in dependent patients. Higher opioid doses to override the blockade risk overdose.
What this interaction means in plain words
Codeine and Olanzapine / samidorphan are not normally used together. Taking them at the same time is expected to cause harm or make one of them unsafe, so a different medicine is usually chosen for one of the two.
Why it happens
Samidorphan is a mu-opioid receptor antagonist that opposes the effects of opioid agonists.
What to do
Allow an opioid-free interval of at least 7 days before starting olanzapine/samidorphan. Choose a different antipsychotic if opioids are needed.
What to ask your pharmacist
- Is there an alternative to one of these two medicines for me?
- If both are essential, who is monitoring me and how often?
- Which symptoms mean I should stop and seek help straight away?
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Other interactions of Codeine
- Alvimopan + Codeine Contraindicated
- Codeine + Isocarboxazid Contraindicated
- Codeine + Phenelzine Contraindicated
- Codeine + Tranylcypromine Contraindicated
- Alfentanil + Codeine Major
- Alprazolam + Codeine Major
Frequently asked questions
Can I take Codeine with Olanzapine / samidorphan?
MediHelp rates the interaction as contraindicated. Codeine and Olanzapine / samidorphan are not normally used together. Taking them at the same time is expected to cause harm or make one of them unsafe, so a different medicine is usually chosen for one of the two. Samidorphan blocks opioid receptors, reducing codeine analgesia and potentially precipitating withdrawal in dependent patients. Higher opioid doses to override the blockade risk overdose.
How serious is the interaction between Codeine and Olanzapine / samidorphan?
MediHelp rates it contraindicated, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Allow an opioid-free interval of at least 7 days before starting olanzapine/samidorphan. Choose a different antipsychotic if opioids are needed.
What other medicines interact with Codeine?
MediHelp also lists interactions of Codeine with, for example, Alvimopan, Isocarboxazid, Phenelzine. The full list is on the Codeine page.
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