Drug interactions
Lithium + Morphine
Severity: Minor
Lithium and Morphine: minor 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
Lithium has been associated with serotonin toxicity when combined with serotonergic agents, and opioids have rarely been implicated. With morphine the risk is low and poorly documented.
What this interaction means in plain words
Lithium and Morphine have a small, usually unimportant interaction. Most people can take both; the pharmacist may still mention it so that any unexpected effect is recognised.
Lithium belongs to Central Nervous System; Morphine belongs to Musculoskeletal.
Why it happens
Possible additive serotonergic effects; not well established.
What to do
No routine change needed; monitor for tremor, agitation, hyperreflexia and fever, and check lithium levels as usual.
What to ask your pharmacist
- Is there anything I should notice while taking both?
- Do I need to tell my doctor at the next visit?
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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 Lithium
- Lithium + Thioridazine Contraindicated
- Lithium + Vandetanib Contraindicated
- Aceclofenac + Lithium Major
- Acemetacin + Lithium Major
- Amisulpride + Lithium Major
- Amlodipine-benazepril + Lithium Major
Frequently asked questions
Can I take Lithium with Morphine?
MediHelp rates the interaction as minor. Lithium and Morphine have a small, usually unimportant interaction. Most people can take both; the pharmacist may still mention it so that any unexpected effect is recognised. Lithium has been associated with serotonin toxicity when combined with serotonergic agents, and opioids have rarely been implicated. With morphine the risk is low and poorly documented.
How serious is the interaction between Lithium and Morphine?
MediHelp rates it minor, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: No routine change needed; monitor for tremor, agitation, hyperreflexia and fever, and check lithium levels as usual.
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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