title: Meta-analysis for bioequivalence studies: interchangeability of generic drugs and similar containing Hydrochlorothiazide is possible but not with Enalapril Maleate.
abstract: BACKGROUND
  The generic drugs program provided a better population's access to medicines. To ensure interchangeability between a brand-name and generic or similar drugs is necessary that they are bioequivalent. With the growing number of generic drugs, it is common for patients to replace a generic to another or one similar. However, this exchange can not guarantee the maintenance of bioequivalence. To evaluate the safety interchangeability between different generic and similar drugs with Hydrochlorothiazide and Enalapril Maleate, a meta-analysis was carried out with several bioequivalence studies with these drugs.
  
  
  METHODS
  Data from bioequivalence of generic and similar drugs approved by the National Health Surveillance Agency (Anvisa) (drug regulatory agency in Brazil) were used. The compatibility of data from each study was analyzed and the determination of a confidence interval for the differences between the means of pharmacokinetic parameters, area under the curve (ASC0-t) and maximum plasma concentration (Cmax), was made for each study by meta-analysis.
  
  
  RESULTS
  The interchangeability between the combinations of the three products with Hydrochlorothiazide was confirmed based on the obtained confidence intervals. For the drugs studied with Enalapril Maleate interchangeability has not been confirmed for 50% of the product comparisons.
  
  
  CONCLUSIONS
  The exchange was established between the three products with hydrochlorothiazide. However, for the Enalapril Maleate half of the products studied are not interchangeable, considering they do not match the established intervals for bioequivalence tests, so the pharmacokinetics behavior and thus the effectiveness of the product may be changed.
authors.affiliation: National Health Surveillance Agency (Agência Nacional de Vigilância Sanitária -Anvisa), Brasília, DF, Brazil. renato.lopes@anvisa.gov.br
authors.forename: Renato Almeida
authors.initials: RA
authors.lastname: Lopes
authors.forename: Francisco de Assis Rocha
authors.initials: Fde A
authors.lastname: Neves
mesh_terms: D000959:Antihypertensive Agents / Q000493:pharmacokinetics*; D057915:Drug Substitution; D004656:Enalapril / Q000493:pharmacokinetics*; D006801:Humans; D006852:Hydrochlorothiazide / Q000493:pharmacokinetics*; D013810:Therapeutic Equivalency
chemical_list: D000959:Antihypertensive Agents; D006852:Hydrochlorothiazide; D004656:Enalapril