CYP2C19, an isozyme of cytochrome P450, plays an important role in the metabolism of a wide spectrum of drugs, including:
• clopidogrel
• proton pump inhibitors
• antidepressants: amitriptyline, clomipramine, imipramine, citalopram, moclobemide
• anticonvulsant & antiepileptic agents: diazepam, primidone, phenytoin, barbiphen, nordazepam
• antimalarial agent: proguanil
• tamoxifen, warfarin, gliclazide, propranolol, cyclophosphamide, nelfinavir, progesterone, teniposide, tetrahydrocannabinol, karisoprodol, voriconazole.
CYP2C19 gene is polymorphous, with common variants encoding enzymes with enhanced, reduced and even absent function. Allele CYP2C19*1 corresponds with wild type, characterised by regular catalytic reactivity of the enzyme. The main polymorphism responsible for the enzyme function loss in European populations is 681G>A, also known as CYP2C19*2. The frequency of this polymorphism reaches 14%. Allelic variant CYP2C19*17 (–806Ñ>T), which determines the enhanced metathesis of enzymatic substrate is also quite common (up to 20%).
