CYP Enzymes

CYP1, 2, 3 → drug and steroid metabolism

CYP4 → arachidonic acid or fatty acid metabolism

• arachidonic acid is involved in the immune response

CYP5 → thromboxane A2 synthase

• blood clotting will be affected

inducing agent → increases rate of metabolism reducing effectiveness of medication

inhibitor → decreases rate of metabolism increasing drug levels

poor metabolizer → phenotype of two variant alleles for “loss-of-function” enzymes

intermediate metabolizers→ only one variant present

extensive metabolizer (normal) → no variant alleles

ultra-rapid metabolizer → *17 variant increases CYP2C19 activity and specificity

• CYP2D6 *2 variant increases enzyme activity

allopurinol → binds to xanthine oxidase to be activated

Pharmacogenetics → study of how genetic variations affect drug disposition

Pharmacogenomics → genetic differences influence drug response

CYP2C19 → Clopidogrel, Diazepam, Lansoprazole

CYP2C9 → Warfarin

VKORC1 → Warfarin

CYP2D6 → Codeine, tramadol, + many psychiatric drugs

TPMP → Thiopurines

SLCO1B1: Simvastatin

CYP3A5 → Tacrolimus

HLA-B/HLA-A → carbamazepine

CYP2C19:CYP2D6→ citalopram, doxepin, escitalopram, amitriptyline

CYP2C19:CYP2C9:CYP2D6→ flibanserin

CYP2C19:CYP2C9→ nelfinavir (viracept)

CYP2C19:CYP2C9: HLA-B →phenytoin

CYP2C19:UGT1A1→ axitinib

CYP2C9:VKORC1→ warfarin

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