Pharmacogenomics

CYP2C19

A cytochrome P450 enzyme that activates the prodrug clopidogrel to its antiplatelet metabolite and also metabolises proton pump inhibitors and several other drugs.

In depth

Loss-of-function alleles such as CYP2C19*2 and *3 reduce formation of the active clopidogrel metabolite; in poor and intermediate metabolizers this lowers platelet inhibition and, after percutaneous coronary intervention, raises the risk of stent thrombosis and other major cardiovascular events, so CPIC recommends an alternative antiplatelet agent not dependent on CYP2C19 activation. The increased-function allele CYP2C19*17 underlies the rapid and ultrarapid phenotypes.

For drugs inactivated by CYP2C19, such as several proton pump inhibitors, the relationship is reversed: poor metabolizers achieve higher drug exposure, which can be advantageous for acid suppression, while ultrarapid metabolizers may have reduced efficacy at standard doses.

Clinical pearl

In a CYP2C19 poor or intermediate metabolizer after coronary stenting, CPIC supports switching from clopidogrel to an antiplatelet that does not require CYP2C19 activation.

Example drugs

Clopidogrel Omeprazole Voriconazole Escitalopram
TRIn Turkish

CYP2C19

Ön ilaç klopidogreli antiplatelet etkili metabolitine dönüştüren; ayrıca proton pompa inhibitörlerini ve başka birçok ilacı metabolize eden bir sitokrom P450 enzimidir.

CYP2C19*2 ve *3 gibi işlev kaybı alelleri, aktif klopidogrel metabolitinin oluşumunu azaltır; zayıf ve ara metabolizörlerde bu durum trombosit inhibisyonunu düşürür ve perkütan koroner girişim sonrasında stent trombozu ile diğer büyük kardiyovasküler olayların riskini artırır; bu nedenle CPIC, CYP2C19 aktivasyonuna bağımlı olmayan alternatif bir antiplatelet ajan önerir. Artmış işlevli alel CYP2C19*17, hızlı ve ultra hızlı fenotiplerin temelini oluşturur.

Bazı proton pompa inhibitörleri gibi CYP2C19 tarafından inaktive edilen ilaçlarda ilişki tersine döner: zayıf metabolizörler daha yüksek ilaç maruziyetine ulaşır ki bu asit baskılanması için avantajlı olabilir; ultra hızlı metabolizörlerde ise standart dozlarda etkinlik azalabilir.

Koroner stent sonrası CYP2C19 zayıf veya ara metabolizör bir hastada CPIC, klopidogrelden CYP2C19 aktivasyonuna ihtiyaç duymayan bir antiplatelet ilaca geçilmesini destekler.

Updated 24.09.2026 0 views Educational reference — verify against current sources before clinical use.

Read next

Poor MetabolizerZayıf Metabolizör

A CPIC phenotype for a person carrying two non-functional (no-function) alleles of a drug-metabolising enzyme gene, resulting in little or no enzyme activity.

 Ultrarapid MetabolizerUltra Hızlı Metabolizör

A CPIC phenotype for a person with increased drug-metabolising enzyme activity, often from a gene duplication or an increased-function allele, above the normal metabolizer range.

 Activity ScoreAktivite Skoru

A numeric value, assigned to each allele and summed across a diplotype, used mainly for CYP2D6 to translate genotype into a predicted metabolizer phenotype.

 Star AlleleYıldız (*) Alel

A standardised naming system for a specific haplotype of a pharmacogenetically important gene, denoted by an asterisk followed by a number, such as CYP2D6*4.

 Cytochrome P450Sitokrom P450

A superfamily of heme-containing monooxygenase enzymes, located mainly in the endoplasmic reticulum of hepatocytes and enterocytes, that catalyze most phase I oxidative drug metabolism.

 CPIC GuidelineCPIC Kılavuzu

A peer-reviewed, evidence-based prescribing recommendation issued by the Clinical Pharmacogenetics Implementation Consortium for a specific gene–drug pair.