Drug interactions
Fluoxetine + Methylene blue
Severity: Contraindicated
Fluoxetine and Methylene blue: contraindicated 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 reversible MAO-A inhibitor and, combined with a serotonergic SSRI such as fluoxetine, can precipitate serotonin syndrome. Features include agitation, hyperthermia, clonus, autonomic instability and seizures.
What this interaction means in plain words
Fluoxetine and Methylene blue are not normally used together. Taking them at the same time is expected to cause harm or make one of them unsafe, so a different medicine is usually chosen for one of the two.
Why it happens
MAO-A inhibition by methylene blue adds to serotonin reuptake inhibition, producing excess serotonergic activity.
What to do
Avoid unless methylene blue is needed urgently for a life-threatening condition; then stop fluoxetine and monitor for serotonin toxicity for several hours to days. Because of fluoxetine's long half-life, do not restart it until the washout period in labeling has been observed.
What to ask your pharmacist
- Is there an alternative to one of these two medicines for me?
- If both are essential, who is monitoring me and how often?
- Which symptoms mean I should stop and seek help straight away?
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Other interactions of Fluoxetine
- Fluoxetine + Isocarboxazid Contraindicated
- Fluoxetine + Mavacamten Contraindicated
- Fluoxetine + Phenelzine Contraindicated
- Fluoxetine + Pimozide Contraindicated
- Fluoxetine + Rasagiline Contraindicated
- Fluoxetine + Selegiline Contraindicated
Frequently asked questions
Can I take Fluoxetine with Methylene blue?
MediHelp rates the interaction as contraindicated. Fluoxetine and Methylene blue are not normally used together. Taking them at the same time is expected to cause harm or make one of them unsafe, so a different medicine is usually chosen for one of the two. Methylene blue is a reversible MAO-A inhibitor and, combined with a serotonergic SSRI such as fluoxetine, can precipitate serotonin syndrome. Features include agitation, hyperthermia, clonus, autonomic instability and seizures.
How serious is the interaction between Fluoxetine and Methylene blue?
MediHelp rates it contraindicated, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Avoid unless methylene blue is needed urgently for a life-threatening condition; then stop fluoxetine and monitor for serotonin toxicity for several hours to days. Because of fluoxetine's long half-life, do not restart it until the washout period in labeling has been observed.
What other medicines interact with Fluoxetine?
MediHelp also lists interactions of Fluoxetine with, for example, Isocarboxazid, Mavacamten, Phenelzine. The full list is on the Fluoxetine page.
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