Variation in the CYP2D6 genotype is not associated with carvedilol dose changes in patients with heart failure

Carvedilol is the standard of care for heart failure (HF) patients. Carvedilol is partially metabolized by the highly polymorphic enzyme, CYP2D6. To reach an effective dose while avoiding adverse drug reactions (ADRs), testing of CYP2D6 genotype prior to carvedilol initiation may be considered. The objectives of this study were to determine CYP2D6 metabolic genotypes in an Israeli cohort of HF patients and to investigate the relationship between genotype, carvedilol dose and number of ADRs to determine the importance of CYP2D6 genotyping prior to treatment initiation.

Ninety-three patients with HF on carvedilol were CYP2D6 genotyped and classified as poor (PM), intermediate (IM), extensive (EM) or ultrarapid (UM) metabolizers. Carvedilol dose and ADRs were calculated and correlated with genotype using linear regression statistic analysis.

The distribution of the CYP2D6 phenotype in the Israeli population with HF is similar to the European general population. There were no significant differences of carvedilol dose and number of ADRs among genotype groups. Genotype group affiliation and number of adverse drug reactions were not predictive of carvedilol dose changes.

Genotype group affiliation and number of adverse drug reactions were not predictive of carvedilol dose during therapy for patients with HF. The Israeli CYP2D6 phenotype distribution in HF patients was consistent with the frequency in the general European population.