The SLCO1B1*5 allele (defined as consisting of rs4149056) is assigned as a no function allele by CPIC. Patients carrying SLCO1B1*5 allele in combination with a normal, no, or increased function allele may have increased simvastatin acid concentration when treated with simvastatin as compared to patients with two normal function alleles. Other genetic and clinical factors may also influence the metabolism of simvastatin. This annotation only covers the pharmacokinetic relationship between SLCO1B1 and simvastatin acid or simvastatin and does not include evidence about clinical outcomes.