Drug interactions
Ketamine + Morphine
Severity: Moderate
Ketamine and Morphine: moderate 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
Ketamine is often combined with opioids for analgesia and can reduce opioid requirements, but the combination can increase sedation and cause hypotension and respiratory depression. Ketamine's psychotomimetic effects may also be altered.
What this interaction means in plain words
Ketamine and Morphine can affect each other. The combination is often manageable, but it may need a change of dose, a change of timing, or extra checks while both are taken.
Ketamine belongs to Central Nervous System; Morphine belongs to Musculoskeletal.
Why it happens
Additive CNS depression from NMDA antagonism and mu-opioid agonism.
What to do
Titrate both drugs carefully and monitor sedation, respiratory rate and blood pressure. Consider reducing the opioid dose when ketamine is added.
What to ask your pharmacist
- Should I take them at different times of day?
- Does the dose of either medicine need to change?
- Is there anything I should avoid, such as alcohol or certain foods, while on both?
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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 Ketamine
Frequently asked questions
Can I take Ketamine with Morphine?
MediHelp rates the interaction as moderate. Ketamine and Morphine can affect each other. The combination is often manageable, but it may need a change of dose, a change of timing, or extra checks while both are taken. Ketamine is often combined with opioids for analgesia and can reduce opioid requirements, but the combination can increase sedation and cause hypotension and respiratory depression. Ketamine's psychotomimetic effects may also be altered.
How serious is the interaction between Ketamine and Morphine?
MediHelp rates it moderate, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Titrate both drugs carefully and monitor sedation, respiratory rate and blood pressure. Consider reducing the opioid dose when ketamine is added.
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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