Drug interactions
Doxepin + Morphine
Severity: Moderate
Doxepin 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
Doxepin is a sedating tricyclic antidepressant, so with morphine it can increase drowsiness and respiratory depression. Its serotonergic activity also gives a small risk of serotonin toxicity, and tricyclics may increase opioid effects.
What this interaction means in plain words
Doxepin 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.
Doxepin belongs to Dermatology; Morphine belongs to Musculoskeletal.
Why it happens
Additive CNS depression plus possible additive serotonergic effects from reuptake inhibition.
What to do
Start with low doses and monitor sedation, respiratory function and signs of serotonin toxicity. Counsel patients to avoid alcohol and driving until the response is known.
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 Doxepin
- Doxepin + Isocarboxazid Contraindicated
- Doxepin + Phenelzine Contraindicated
- Doxepin + Procarbazine Contraindicated
- Doxepin + Safinamide Contraindicated
- Doxepin + Selegiline Contraindicated
- Doxepin + Tranylcypromine Contraindicated
Frequently asked questions
Can I take Doxepin with Morphine?
MediHelp rates the interaction as moderate. Doxepin 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. Doxepin is a sedating tricyclic antidepressant, so with morphine it can increase drowsiness and respiratory depression. Its serotonergic activity also gives a small risk of serotonin toxicity, and tricyclics may increase opioid effects.
How serious is the interaction between Doxepin 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, respiratory function and signs of serotonin toxicity. Counsel patients to avoid alcohol and driving until the response is known.
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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