The CYP3A5*1 allele has been assigned as a normal function allele by CPIC. Patients who are recipients of a kidney, heart, lung or hematopoietic stem cell transplant or a liver transplant with the same CYP3A5 genotype as the recipient and who carry the *1 allele in combination with a normal or no function allele may have increased metabolism of tacrolimus as compared to patients carrying two no function alleles. However, conflicting evidence has been reported. This annotation only covers the pharmacokinetic relationship between CYP3A5 and tacrolimus and does not include evidence about clinical outcomes. Other genetic and clinical factors may also affect tacrolimus metabolism.