title: Bioequivalence of generic drugs.
abstract: Generic drugs are bioequivalent to the original brand; this is a prerequisite for marketing approval. It is theoretically possible that one generic drug may overestimate the pharmacokinetic (PK) parameters of the original and another generic may underestimate these PK parameters; in consequence, these 2 generics may not be bioequivalent between themselves. The result could be loss of efficacy or development of drug-related adverse effects if these generics are interchanged in stable patients. In a recent study involving 292 indirect comparisons of generic formulations of 9 different drugs, mathematical modeling showed that in most cases (87.0% for maximum concentration, 90.1% for area under the curve, and 80.5% for both) generic drugs are bioequivalent to each other. These reassuring findings notwithstanding, prudence dictates that, in stable patients, generic drugs should be interchanged only if there is a good reason for it. This is because bioequivalent brands of drugs may differ in their excipient content, and this can result in variations in safety profiles.
authors.affiliation: Department of Psychopharmacology, National Institute of Mental Health and Neurosciences, Bangalore, India candrade@psychiatrist.com.
authors.forename: Chittaranjan
authors.initials: C
authors.lastname: Andrade
mesh_terms: D016568:Drugs, Generic / Q000009:adverse effects / Q000493:pharmacokinetics*; D005079:Excipients / Q000009:adverse effects; D006801:Humans; D013810:Therapeutic Equivalency
chemical_list: D016568:Drugs, Generic; D005079:Excipients