Drug interactions
Fluvoxamine + Mexiletine
Severity: Major
Fluvoxamine and Mexiletine: major 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
Mexiletine is metabolized partly by CYP1A2 and CYP2D6, and fluvoxamine strongly inhibits CYP1A2, so mexiletine exposure can increase. This raises the risk of neurologic and gastrointestinal adverse effects and proarrhythmia.
What this interaction means in plain words
Fluvoxamine and Mexiletine 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.
Fluvoxamine belongs to Central Nervous System; Mexiletine belongs to Cardiovascular.
Why it happens
Fluvoxamine inhibits CYP1A2 (and to a lesser extent other enzymes), reducing mexiletine clearance.
What to do
Reduce the mexiletine dose and monitor for toxicity and ECG changes, or choose an alternative antidepressant that does not inhibit CYP1A2.
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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Other interactions of Mexiletine
- Fezolinetant + Mexiletine Contraindicated
- Mexiletine + Pimozide Contraindicated
- Alosetron + Mexiletine Major
- Amiodarone + Mexiletine Major
- Clozapine + Mexiletine Major
- Cobicistat + Mexiletine Major
Other interactions of Fluvoxamine
- Agomelatine + Fluvoxamine Contraindicated
- Alosetron + Fluvoxamine Contraindicated
- Fezolinetant + Fluvoxamine Contraindicated
- Fluvoxamine + Isocarboxazid Contraindicated
- Fluvoxamine + Mavacamten Contraindicated
- Fluvoxamine + Methylene blue Contraindicated
Frequently asked questions
Can I take Fluvoxamine with Mexiletine?
MediHelp rates the interaction as major. Fluvoxamine and Mexiletine 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. Mexiletine is metabolized partly by CYP1A2 and CYP2D6, and fluvoxamine strongly inhibits CYP1A2, so mexiletine exposure can increase. This raises the risk of neurologic and gastrointestinal adverse effects and proarrhythmia.
How serious is the interaction between Fluvoxamine and Mexiletine?
MediHelp rates it major, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Reduce the mexiletine dose and monitor for toxicity and ECG changes, or choose an alternative antidepressant that does not inhibit CYP1A2.
What other medicines interact with Mexiletine?
MediHelp also lists interactions of Mexiletine with, for example, Fezolinetant, Pimozide, Alosetron. The full list is on the Mexiletine page.
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