The CYP2D6*1 allele is assigned as a normal function allele by CPIC. Patients carrying the *1 allele in combination with alleles that result in a normal metabolizer phenotype may have higher clearance of flecainide as compared to patients carrying two no function alleles; two decreased function alleles with an activity value of 0.25; or a no function allele in combination with a normal function allele or a decreased function allele with an activity value of 0.25. However, conflicting evidence has been reported. Other genetic and clinical factors may also influence flecainide metabolism. This annotation only covers the pharmacokinetic relationship between CYP2D6 and flecainide and does not include evidence about clinical outcomes.