Medicine Shortages: An Algorithm for Evaluating the Substitution with Equivalent or Alternative Products

Drug shortages are a serious issue affecting health systems worldwide whose multiple causes include supply issues, regulatory limitations, market distortions, and whose possible repercussions on patients may impair therapy efficacy. Despite numerous actions implemented by regulatory authorities, including market monitoring, export restrictions and temporary regulation mitigations, few instruments have been made available to help health operators find marketed alternatives to unavailable products. The aim of this work was to create an algorithm to find equivalent or alternative medicinal products available in a certain pharmaceutical market; algorithm development and validation have been performed using the medicinal products marketed in Italy. First, a new assembled code, describing the active pharmaceutical ingredient by Anatomical Therapeutical Chemical (ATC) code, and its dosage form by European Directorate for the Quality of Medicines & HealthCare (EDQM) Standard Terms, has been attributed to each marketed medicinal product. Then, the algorithm has been set up to identify its possible equivalents or alternatives by assigning a score quantifying differences in Defined Daily Dose (DDD) per presentation unit and in characterizing Standard Terms. The algorithm has been validated on a randomized sample of medicinal products, proving to be able to identify appropriate equivalents or alternatives; moreover, it has been tested in real conditions by submitting a survey to health professionals, who found this product reliable and useful. The developed algorithm may be employed as a rational tool to help health operators find solutions to drug shortages. The work has highlighted some limits of the current ATC attribution that should be addressed by competent authorities.