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Tizanidine Effects Increased by Strong, Moderate 1A2 Inhibitors

KEY POINT

Serum concentrations of the centrally acting skeletal muscle relaxant tizanidine are increased during concomitant therapy with inhibitors of the cytochrome P450 1A2 isoenzyme, including fluvoxamine and ciprofloxacin.

SOURCES

Granfors MT et al. Ciprofloxacin greatly increases concentrations and hypotensive effect of tizanidine by inhibiting its cytochrome P450 1A2-mediated presystemic metabolism. Clin Pharmacol Ther. 2004;76:598–606.

Granfors MT et al. Fluvoxamine drastically increases concentrations and effects of tizanidine: a potentially hazardous interaction. Clin Pharmacol Ther. 2004;75:331–41.

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