The SLCO1B1*1 allele is assigned as a normal function allele by CPIC. Patients carrying SLCO1B1*1 allele in combination with another normal function allele may have a lower risk of atorvastatin-related myopathy when treated with atorvastatin as compared to patients with a no function allele in combination with a normal or increased function allele or with two no function alleles. However, conflicting evidence has been reported. Other genetic and clinical factors may also influence the toxicity of atorvastatin.