A Survey of the Structures of US FDA Approved Combination Drugs.

Combination drugs are an important class of US FDA approved pharmaceuticals. These drugs have been on a continuous growth trajectory since the first combination drugs were approved in the 1940s. In this Perspective, we report the first comprehensive compilation and analysis of US FDA approved combination drugs, from the first approval in 1943 through 2018. Our database contains 419 combination drugs, which are represented by 328 unique small molecule structures. Breakdown of these drugs according to disease category, structure, combination composition, and year of approval is presented as well as the top 24 most commonly used small molecule combination drug components. For frequently used small molecule components, we present "relationship diagrams" to aid in the visualization of the many drug combinations these structures are part of. The main body contains 10 disease-focused sections wherein every small molecule component utilized as part of a combination for each disease category is displayed.