Drug interactions
Meperidine + Morphine
Severity: Major
Meperidine and Morphine: major 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
Two opioid agonists together produce additive analgesia, sedation and respiratory depression, and there is no therapeutic reason to combine them routinely. Meperidine's neurotoxic metabolite normeperidine can accumulate, especially in renal impairment, and meperidine carries serotonin syndrome risk.
What this interaction means in plain words
Meperidine and Morphine 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.
Meperidine belongs to Musculoskeletal; Morphine belongs to Musculoskeletal.
Why it happens
Additive mu-opioid receptor agonism; meperidine also has serotonergic activity.
What to do
Avoid concurrent use of multiple opioids where possible and do not use meperidine for prolonged therapy. If combined, use the lowest doses and monitor respiratory rate and sedation.
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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Other interactions of Morphine
- Alvimopan + Morphine Contraindicated
- Isocarboxazid + Morphine Contraindicated
- Morphine + Olanzapine / samidorphan Contraindicated
- Morphine + Phenelzine Contraindicated
- Morphine + Tranylcypromine Contraindicated
- Alfentanil + Morphine Major
Other interactions of Meperidine
- Alvimopan + Meperidine Contraindicated
- Isocarboxazid + Meperidine Contraindicated
- Meperidine + Methylene blue Contraindicated
- Meperidine + Olanzapine / samidorphan Contraindicated
- Meperidine + Phenelzine Contraindicated
- Meperidine + Procarbazine Contraindicated
Frequently asked questions
Can I take Meperidine with Morphine?
MediHelp rates the interaction as major. Meperidine and Morphine 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. Two opioid agonists together produce additive analgesia, sedation and respiratory depression, and there is no therapeutic reason to combine them routinely. Meperidine's neurotoxic metabolite normeperidine can accumulate, especially in renal impairment, and meperidine carries serotonin syndrome risk.
How serious is the interaction between Meperidine and Morphine?
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 concurrent use of multiple opioids where possible and do not use meperidine for prolonged therapy. If combined, use the lowest doses and monitor respiratory rate and sedation.
What other medicines interact with Morphine?
MediHelp also lists interactions of Morphine with, for example, Alvimopan, Isocarboxazid, Olanzapine / samidorphan. The full list is on the Morphine page.
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