December 31, 2012
Combination drugs, also known as fixed-dose combinations, are combinations of two or more active drug ingredients formulated into a single tablet. Combination of previously marketed products became a common strategy for pharmaceutical companies to get patent extensions especially after the implementation of the Waxman-Hatch Act in 1984, which lowered the barrier for generic drug entry. There is a concern on the overutilization of combination drugs, the safety and quality of these drugs, and the economic burden to public health programs and consumers due to pricing strategies of the pharmaceutical companies. This study assesses the effects of utilization of combination drugs in patient adherence, medication possession ratio, and adverse effects caused by potential drug interactions among individual active ingredients. The study also evaluates the costs and market discontinuation ratio of combination drugs compared to single products.