Drug interactions
Mirtazapine + Morphine
Severity: Moderate
Mirtazapine 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
Mirtazapine is strongly sedating, so with morphine the CNS depression is additive. Serotonin syndrome is rarely reported with opioids and serotonergic antidepressants, though morphine carries little serotonergic risk.
What this interaction means in plain words
Mirtazapine 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.
Mirtazapine belongs to Central Nervous System; Morphine belongs to Musculoskeletal.
Why it happens
Additive CNS depression via antihistaminic effects of mirtazapine plus opioid effects.
What to do
Start with low doses and monitor sedation and respiratory status. Watch for signs of serotonin toxicity such as clonus, agitation and fever.
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 Mirtazapine
- Isocarboxazid + Mirtazapine Contraindicated
- Mirtazapine + Phenelzine Contraindicated
- Mirtazapine + Pimozide Contraindicated
- Mirtazapine + Procarbazine Contraindicated
- Mirtazapine + Rasagiline Contraindicated
- Mirtazapine + Selegiline Contraindicated
Frequently asked questions
Can I take Mirtazapine with Morphine?
MediHelp rates the interaction as moderate. Mirtazapine 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. Mirtazapine is strongly sedating, so with morphine the CNS depression is additive. Serotonin syndrome is rarely reported with opioids and serotonergic antidepressants, though morphine carries little serotonergic risk.
How serious is the interaction between Mirtazapine 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: Start with low doses and monitor sedation and respiratory status. Watch for signs of serotonin toxicity such as clonus, agitation and fever.
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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