CMPD101 is a novel, potent and selective G-protein coupled receptor kinase 2 and 3 (GRK2/GRK3) inhibitor (IC50 values are 35 and 32 nM at GRK2 and GRK3 respectively). CMPD101 exhibits selectivity for GRK2/3 over GRK1/5 and reduces DAMGO-induced desensitization and internalization of μ-opioid receptors. CMPD101 has been shown to potentiate phosphatidylinositol 4,5-bisphosphate (PIP2) depletion and slow agonist-induced desensitization of protease-activated receptor 2 (PAR2).