Product Description: Hydroxymethyl tolperisone hydrochloride is a metabolite of Tolperisone (HY-B1139A). Hydroxymethyl tolperisone hydrochloride is formed from tolperisone primarily by the cytochrome P450 (CYP) isoform CYP2D6 and to a lesser extent by CYP2C19 and CYP1A2.