Drug interactions
Duloxetine + Morphine
Severity: Moderate
Duloxetine 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
Opioids combined with serotonin-norepinephrine reuptake inhibitors carry a risk of serotonin syndrome, which may present with agitation, tremor, hyperthermia, clonus and autonomic instability. Duloxetine also inhibits CYP2D6, though this matters little for morphine, which is cleared mainly by glucuronidation.
What this interaction means in plain words
Duloxetine 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.
Duloxetine belongs to Central Nervous System; Morphine belongs to Musculoskeletal.
Why it happens
Additive serotonergic effects (morphine has weak serotonergic activity) plus CYP2D6 inhibition by duloxetine.
What to do
Monitor for features of serotonin syndrome, particularly after starting or increasing either drug. Stop the serotonergic agents and give supportive care if symptoms develop.
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 Duloxetine
- Duloxetine + Isocarboxazid Contraindicated
- Duloxetine + Linezolid Contraindicated
- Duloxetine + Methylene blue Contraindicated
- Duloxetine + Phenelzine Contraindicated
- Duloxetine + Procarbazine Contraindicated
- Duloxetine + Rasagiline Contraindicated
Frequently asked questions
Can I take Duloxetine with Morphine?
MediHelp rates the interaction as moderate. Duloxetine 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. Opioids combined with serotonin-norepinephrine reuptake inhibitors carry a risk of serotonin syndrome, which may present with agitation, tremor, hyperthermia, clonus and autonomic instability. Duloxetine also inhibits CYP2D6, though this matters little for morphine, which is cleared mainly by glucuronidation.
How serious is the interaction between Duloxetine 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: Monitor for features of serotonin syndrome, particularly after starting or increasing either drug. Stop the serotonergic agents and give supportive care if symptoms develop.
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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