Poor-Quality and Counterfeit Drugs: A Systematic Assessment of Prevalence and Risks Based on Data Published From 2007 to 2016

Counterfeit drugs can hurt patients and harm the pharmaceutical industry. In 2006, the International Medical Products Anti-Counterfeiting Taskforce expressed a need to generate more and better data to calculate a worldwide prevalence of counterfeiting. This review analyzes field test data that were published in the time frame January 2007 to December 2016, were accessible via Pubmed, and which addressed the prevalence of counterfeit drugs. Based on the 41 studies identified, it is still not possible to make a reliable statement about the prevalence of counterfeit drugs due to the heterogeneity of the results. To make further progress in this area, both the quantity and quality of documented field tests should be increased. Without a differentiated analysis considering therapeutic class, source, and country of counterfeit drugs, it will remain difficult to identify the root causes of market infiltration and useful points of attack to combat them. Studies with high sample power and randomized sampling, packaging inspection, and detailed chemical analysis will be necessary to correctly identify (especially professional) counterfeit samples. The classification system presented in this review should help to calculate not only the prevalence of counterfeit drugs but also the risks to the patient associated with different types of counterfeited medicines.