Journal of Pharmacy and Pharmacology 2013-09-01

Metoprolol oxidation polymorphism in Brazilian elderly cardiac patients.

Daniel Valente Neves, Vera Lucia Lanchote, Luiz de Souza, Miyeko Hayashida, Maria Sueli Nogueira, Natália Valadares de Moraes, Evandro José Cesarino

Index: J. Pharm. Pharmacol. 65(9) , 1347-53, (2013)

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Abstract

The purpose of this study was to phenotype the CYP2D6 in elderly with heart disease classified as extensive metabolizer or poor metabolizers (PM) of metoprolol, develop and validate the method of analysis of metoprolol tartrate and its metabolite in urine using HPLC, and identify potential correlations between anthropometric factors with metabolic ratios of metoprolol/α-OH metoprolol in urine.The sample was composed of 130 elderly individuals with a previously identified type of heart condition, with normal renal and hepatic functions. The urine of all the patients were collected 0-8 h after the administration of a pill of 100 mg of metoprolol to determine concentrations of metoprolol and α-hydroxymetoprolol. Those patients presenting a metabolic ratio greater than 12.6 were phenotyped as PM.The median age of patients was 71.0 years, with a minimum of 60 and maximum of 93 years old. Three patients (2.3%) were phenotyped as PM of metoprolol different from the rate (7-10%) of PM existing in the Caucasian population.Most of the studied individuals were women, and the proportion of elderly with heart disease classified as PM was smaller than what is usually found among Caucasian populations.© 2013 University of Sao Paulo. JPP © 2013 Royal Pharmaceutical Society.