SLCO1B1 encodes organic anion transporting polypeptide 1B1 (OATP1B1), a sodium-independent transporter mediating hepatic uptake of diverse organic anions 123. The transporter exhibits broad substrate specificity, transporting bile acids, conjugated steroids, eicosanoids, thyroid hormones (T3 and T4), bilirubin glucuronides, and coproporphyrins 1245. Clinically, SLCO1B1 is critical for hepatic statin uptake, transporting simvastatin, pravastatin, pitavastatin, atorvastatin, and rosuvastatin 627. The common T521C polymorphism significantly impacts statin-associated musculoskeletal symptoms (SAMS), with C allele carriers showing 2-3 fold increased myopathy risk, particularly with simvastatin 879. SLCO1B1 also transports methotrexate and antihypertensive agents including enalapril and valsartan 1011. The transporter's pH-sensitive specificity and HCO3− counter-anion exchange mechanism enable substrate regulation in hepatic microenvironments 4. Genetic variation significantly alters systemic drug exposure, making SLCO1B1 genotyping essential for simvastatin dosing and beneficial for atorvastatin and rosuvastatin therapy optimization 9.