Metoprolol oxidation polymorphism in Brazilian elderly cardiac patients.
OBJECTIVE
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.


METHODS
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.


RESULTS
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.


CONCLUSIONS
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.
School of Pharmaceutical Sciences of Ribeirão Preto, University of São Paulo, Ribeirão Preto, São Paulo, Brazil. danvn83@fcfrp.usp.br
Daniel Valente
DV
Neves
Vera Lucia
VL
Lanchote
Luiz
L
de Souza
Miyeko
M
Hayashida
Maria Sueli
MS
Nogueira
Natália Valadares
NV
de Moraes
Evandro José
EJ
Cesarino
D058671:Adrenergic beta-1 Receptor Antagonists / Q000378:metabolism* / Q000493:pharmacokinetics / Q000652:urine; D000368:Aged; D000369:Aged, 80 and over; D000886:Anthropometry; D044383:Black People / Q000235:genetics; D001938:Brazil; D002851:Chromatography, High Pressure Liquid / Q000379:methods*; D019389:Cytochrome P-450 CYP2D6 / Q000235:genetics / Q000378:metabolism*; D005260:Female; D006331:Heart Diseases / Q000188:drug therapy / Q000208:ethnology / Q000652:urine; D006801:Humans; D008658:Inactivation, Metabolic; D008297:Male; D008790:Metoprolol / Q000031:analogs & derivatives / Q000378:metabolism* / Q000493:pharmacokinetics / Q000652:urine; D008875:Middle Aged; D010084:Oxidation-Reduction; D010641:Phenotype; D011110:Polymorphism, Genetic; D016482:Urinalysis; D044465:White People / Q000235:genetics
D058671:Adrenergic beta-1 Receptor Antagonists; C029504:alpha-hydroxymetoprolol; D019389:Cytochrome P-450 CYP2D6; D008790:Metoprolol
CYP2D6; elderly; metoprolol; phenotype; polymorphism