CCG258747 is a selective GRK2 inhibitor (IC50=18 nM) with high selectivity over GRK1, GRK5, PKA, and ROCK1 (518, 83, >5500, and >550–fold, respectively).CCG258747 also blocks the internalization of the µ-opioid receptor. G protein-coupled receptor (GPCR) kinases (GRKs) are attractive targets for the research of heart failure.