Impact of the ultrarapid metabolizer genotype of cytochrome P450 2D6 on metoprolol pharmacokinetics and pharmacodynamics.

Introduction: In the treatment of heart failure and hypertension with metoprolol, ultrarapid metabolizers (UMs) may not achieve optimal target concentrations with recommended doses. We compared metoprolol pharmacokinetics and effects in UMs with extensive metabolizers (EMs) and with poor metabolizers (PM) as an additional reference group.

Methods: After a single dose of 100 mg metoprolol, pharmacokinetics, resting and exercise heart rate, and blood pressure were analyzed in relation to the CYP2D6 genotypes.