Drug interactions
Fluoxetine + Methamphetamine
Severity: Major
Fluoxetine and Methamphetamine: major interaction.
Last updated Sources: US FDA label
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
Fluoxetine inhibits CYP2D6, which participates in methamphetamine metabolism, so methamphetamine exposure may increase. Both drugs affect monoamines, so there is a risk of serotonin toxicity, hypertension and tachycardia.
What this interaction means in plain words
Fluoxetine and Methamphetamine can interact in a way that may be serious. Using them together is sometimes necessary, but it needs a deliberate decision by the prescriber, a plan for monitoring, and clear advice on the warning signs to watch for.
Fluoxetine belongs to Central Nervous System; Methamphetamine belongs to Central Nervous System.
Why it happens
Fluoxetine inhibition of CYP2D6 plus additive serotonergic and sympathomimetic effects.
What to do
Avoid the combination where possible. If methamphetamine is prescribed, monitor blood pressure, heart rate and signs of serotonin toxicity and use the lowest effective dose.
What to ask your pharmacist
- Does the benefit of taking both outweigh the risk in my case?
- Do I need any blood test, ECG or other check while on both?
- What early warning signs should I watch for, and what should I do if they appear?
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References
Other interactions of Fluoxetine
- Fluoxetine + Isocarboxazid Contraindicated
- Fluoxetine + Mavacamten Contraindicated
- Fluoxetine + Methylene blue Contraindicated
- Fluoxetine + Phenelzine Contraindicated
- Fluoxetine + Pimozide Contraindicated
- Fluoxetine + Rasagiline Contraindicated
Other interactions of Methamphetamine
- Isocarboxazid + Methamphetamine Contraindicated
- Linezolid + Methamphetamine Contraindicated
- Methamphetamine + Phenelzine Contraindicated
- Methamphetamine + Procarbazine Contraindicated
- Methamphetamine + Rasagiline Contraindicated
- Methamphetamine + Safinamide Contraindicated
Frequently asked questions
Can I take Fluoxetine with Methamphetamine?
MediHelp rates the interaction as major. Fluoxetine and Methamphetamine can interact in a way that may be serious. Using them together is sometimes necessary, but it needs a deliberate decision by the prescriber, a plan for monitoring, and clear advice on the warning signs to watch for. Fluoxetine inhibits CYP2D6, which participates in methamphetamine metabolism, so methamphetamine exposure may increase. Both drugs affect monoamines, so there is a risk of serotonin toxicity, hypertension and tachycardia.
How serious is the interaction between Fluoxetine and Methamphetamine?
MediHelp rates it major, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Avoid the combination where possible. If methamphetamine is prescribed, monitor blood pressure, heart rate and signs of serotonin toxicity and use the lowest effective dose.
What other medicines interact with Fluoxetine?
MediHelp also lists interactions of Fluoxetine with, for example, Isocarboxazid, Mavacamten, Methylene blue. The full list is on the Fluoxetine page.
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