Drug interactions
Fluvoxamine + Mirtazapine
Severity: Moderate
Fluvoxamine and Mirtazapine: 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
Fluvoxamine can raise mirtazapine concentrations through CYP1A2 and CYP3A4 inhibition, increasing sedation and adverse effects. Combined use also carries a risk of serotonin syndrome, and mirtazapine has a small QT effect at higher doses.
What this interaction means in plain words
Fluvoxamine and Mirtazapine 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.
Fluvoxamine belongs to Central Nervous System; Mirtazapine belongs to Central Nervous System.
Why it happens
Fluvoxamine inhibition of CYP1A2 and CYP3A4 metabolism of mirtazapine, plus additive serotonergic effects.
What to do
Start mirtazapine at a low dose and titrate cautiously, monitoring sedation and serotonin toxicity signs. Obtain an ECG if other QT risk factors are present.
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 Fluvoxamine
- Agomelatine + Fluvoxamine Contraindicated
- Alosetron + Fluvoxamine Contraindicated
- Fezolinetant + Fluvoxamine Contraindicated
- Fluvoxamine + Isocarboxazid Contraindicated
- Fluvoxamine + Mavacamten Contraindicated
- Fluvoxamine + Methylene blue Contraindicated
Other interactions of Mirtazapine
- Isocarboxazid + Mirtazapine Contraindicated
- Mirtazapine + Phenelzine Contraindicated
- Mirtazapine + Pimozide Contraindicated
- Mirtazapine + Procarbazine Contraindicated
- Mirtazapine + Rasagiline Contraindicated
- Mirtazapine + Selegiline Contraindicated
Frequently asked questions
Can I take Fluvoxamine with Mirtazapine?
MediHelp rates the interaction as moderate. Fluvoxamine and Mirtazapine 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. Fluvoxamine can raise mirtazapine concentrations through CYP1A2 and CYP3A4 inhibition, increasing sedation and adverse effects. Combined use also carries a risk of serotonin syndrome, and mirtazapine has a small QT effect at higher doses.
How serious is the interaction between Fluvoxamine and Mirtazapine?
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 mirtazapine at a low dose and titrate cautiously, monitoring sedation and serotonin toxicity signs. Obtain an ECG if other QT risk factors are present.
What other medicines interact with Fluvoxamine?
MediHelp also lists interactions of Fluvoxamine with, for example, Agomelatine, Alosetron, Fezolinetant. The full list is on the Fluvoxamine page.
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