Drug interactions
Codeine + Methylene blue
Severity: Moderate
Codeine and Methylene blue: 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
Methylene blue is a potent MAO-A inhibitor and can precipitate serotonin syndrome with serotonergic drugs. Codeine has weak serotonergic activity, so the risk is lower than for stronger agents but still present.
What this interaction means in plain words
Codeine and Methylene blue 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
MAO-A inhibition by methylene blue leading to excess serotonin, with weak serotonergic effects of codeine.
What to do
Prefer a non-serotonergic analgesic around methylene blue infusion. If codeine is needed, monitor for agitation, tremor, hyperthermia and clonus.
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 Codeine
- Alvimopan + Codeine Contraindicated
- Codeine + Isocarboxazid Contraindicated
- Codeine + Olanzapine / samidorphan Contraindicated
- Codeine + Phenelzine Contraindicated
- Codeine + Tranylcypromine Contraindicated
- Alfentanil + Codeine Major
Frequently asked questions
Can I take Codeine with Methylene blue?
MediHelp rates the interaction as moderate. Codeine and Methylene blue 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. Methylene blue is a potent MAO-A inhibitor and can precipitate serotonin syndrome with serotonergic drugs. Codeine has weak serotonergic activity, so the risk is lower than for stronger agents but still present.
How serious is the interaction between Codeine and Methylene blue?
MediHelp rates it moderate, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Prefer a non-serotonergic analgesic around methylene blue infusion. If codeine is needed, monitor for agitation, tremor, hyperthermia and clonus.
What other medicines interact with Codeine?
MediHelp also lists interactions of Codeine with, for example, Alvimopan, Isocarboxazid, Olanzapine / samidorphan. The full list is on the Codeine page.
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