Drug interactions
Marijuana + Morphine
Severity: Moderate
Marijuana 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
Cannabis adds to opioid sedation, dizziness and cognitive impairment. Cannabinoids may also modestly enhance opioid analgesia, which can complicate dosing. Morphine is not meaningfully dependent on CYP2D6.
What this interaction means in plain words
Marijuana 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.
Why it happens
Additive CNS depressant effects from cannabinoid receptor activation and opioid agonism.
What to do
Counsel patients about additive sedation and impaired driving, and monitor sedation and respiratory status when starting or increasing morphine.
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
Frequently asked questions
Can I take Marijuana with Morphine?
MediHelp rates the interaction as moderate. Marijuana 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. Cannabis adds to opioid sedation, dizziness and cognitive impairment. Cannabinoids may also modestly enhance opioid analgesia, which can complicate dosing. Morphine is not meaningfully dependent on CYP2D6.
How serious is the interaction between Marijuana 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: Counsel patients about additive sedation and impaired driving, and monitor sedation and respiratory status when starting or increasing morphine.
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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