title: CYP 2D6*4 polymorphism and interindividual response variation to metoprolol in stage 1 hypertensive patients: no association in a rural Indian population?
abstract: OBJECTIVE
  Genetic polymorphism of CYP2D6 shows diverse pharmacokinetic and pharmacodynamic variation. Therefore, the present work was designed to study the variation in therapeutic responses to metoprolol (MP) in stage 1 hypertensive patients and also aims to verify the association of CYP2D6*4 polymorphism and response variation in an Indian population for the first time.
  
  
  METHODS
  Clinically, a total of 119 hypertensive patients and 116 healthy individuals as controls were included. Patients were treated with MP extended release 25 mg tablets once daily for 2 weeks. Reduction in systolic blood pressure, diastolic blood pressure, and pulse rate were recorded before and after the treatment. For genotyping, genotypes of 89 hypertensive patients and 71 healthy controls were investigated for CYP2D6*4 polymorphism.
  
  
  RESULTS
  Based on reduction in systolic blood pressure, 26% of the patients did not respond to the MP treatment. Of the patients that responded, 28% responded very slowly, 35% (19 males, 23 females) responded moderately, and 12% (8 males, 6 females) showed a good response to MP. For genotype analysis, we pooled 89 hypertensive patients and 71 controls. No association was found between CYP2D6*4 polymorphism and MP response.
  
  
  CONCLUSIONS
  We found no relationship between MP response and CYP2D6*4 genotype in an Indian population in our study.
authors.forename: Rajagopal
authors.initials: R
authors.lastname: Ayyappadihas
authors.forename: Unnikrishnan
authors.initials: U
authors.lastname: Dhanalekshmi
authors.forename: Helliah
authors.initials: H
authors.lastname: Jestin
mesh_terms: D058671:Adrenergic beta-1 Receptor Antagonists / Q000008:administration & dosage / Q000009:adverse effects / Q000493:pharmacokinetics; D000328:Adult; D001794:Blood Pressure / Q000187:drug effects; D019389:Cytochrome P-450 CYP2D6 / Q000235:genetics*; D003692:Delayed-Action Preparations / Q000008:administration & dosage / Q000009:adverse effects / Q000493:pharmacokinetics; D016903:Drug Monitoring; D004351:Drug Resistance / Q000235:genetics*; D005260:Female; D006801:Humans; D006973:Hypertension / Q000188:drug therapy / Q000503:physiopathology; D007194:India; D008297:Male; D008790:Metoprolol / Q000008:administration & dosage / Q000009:adverse effects / Q000493:pharmacokinetics; D008875:Middle Aged; D011110:Polymorphism, Genetic; D012424:Rural Population; D012720:Severity of Illness Index
chemical_list: D058671:Adrenergic beta-1 Receptor Antagonists; D003692:Delayed-Action Preparations; D019389:Cytochrome P-450 CYP2D6; D008790:Metoprolol