Like catching two fish with one worm, treating two problems with a single drug is efficient, but exceedingly difficult. In particular, for new diabetes medications, in which one drug aims to tackle two major complications of diabetes—the excess of both lipids and glucose in the blood—the therapeutic benefits, while great, frequently are accompanied by dangerous toxic effects to the heart.
source https://www.lifetechnology.com/blogs/life-technology-medical-news/scientists-solve-mystery-underlying-heart-toxicity-caused-by-diabetes-drugs