Ideal microbiological and pharmacological characteristics of a quality antimicrobial agent: comparing original and generic molecules.

ABSTRACT

This article critically evaluates the main in vitro and in vivo studies published which compare generic with the original molecules, both those administered orally and parenterally. The authors indicate that caution should be used in assuming bioequivalence of the generic drug with its clinical efficacy in clinical practice. In fact, mild differences in the content of the active ingredient, less relevant in healthy volunteers, may have an impact in the actual population, which is heterogeneous for age, sex, weight, concomitant risk factors and severity of the underlying disease, as in critically ill patients, with consequences for the patient and ecosystem. Nowadays the requirements for authorization to commercialize a generic antimicrobial agent are focused on demonstration of bioequivalence to the original molecule, with a range variability of +/-20%. However this kind of trial is not sufficient to predict the actual profile in clinical practice, particularly in critically ill patients. Thus while generics can represent an opportunity for physicians, patients and healthcare systems the regulatory procedures do not seem exhaustive, and it is probably necessary to define an ad hoc technical standard of quality before their commercialization and to perform adequate clinical trials regarding efficacy and safety of the "equivalent molecule", especially for drugs used in critically ill patients.