Mexiletine fluvoxamine

Drugs that may affect mexiletine include aluminum-magnesium hydroxide, atropine, narcotics, cimetidine, fluvoxamine, hydantoins, metoclopramide, propafenone, rifampin, urinary acidifiers, and urinary alkalinizers. 

Smoking cessation, with or without nicotine substitutes, may alter response to concomitant medication in ex-smokers. Smoking may affect alcohol, benzodiazepines, beta-adrenergic blockers, caffeine, clozapine, fluvoxamine, olanzapine, tacrine, theophylline, clorazepate, lidocaine (oral), estradiol, flecanide, imipramine, heparin, insulin, mexiletine, opioids, propranolol, catecholamines, and cortisol. 

A2 Fluvoxamine Ciprofloxacin, mexiletine, propafenone, zileuton Acyclovir, cimetidine, famotidine, norfloxacin, verapamil... 

Mexiletine is metabolized by CYP2D6, CYP1A2, and CYP3A4 fluvoxamine inhibits CYP1A2. It is not surprising therefore that fluvoxamine 50 mg bd for 7 days increased the Cmax and AUC of a single oral dose of mexiletine 200 mg in six healthy Japanese men (43). 

Kusumoto M, Ueno K, Oda A, Takeda K, Mashimo K, Takaya K, Fujimura Y, Nishihori T, Tanaka K. Effect of fluvoxamine on the pharmacokinetics of mexiletine in healthy Japanese men. Clin Pharmacol Ther 2001 69(3) 104-7. 

Fluvoxamine markedly increases the AUC of mexiletine by inhibiting CYP1A2. Fluoxetine and paroxetine might also be expected to interact, albeit by inhibiting CYP2D6, but sertraline is possibly unlikely to interact. 

Fluvoxamine 50 mg twice daily for 7 days increased the AUC of a single 200-mg dose of mexiletine by 55%, and decreased the clearance by 37% in 6 healthy subjects. It is likely that fluvoxamine decreases the metabolism of mexiletine by inhibiting the cytochrome P450 isoenzyme CYP1A2, which is partially responsible fortiie metabolism of mexiletine. The large changes in mexiletine AUC suggest that concurrent therapy should be well monitored. 

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