Potent Rho kinase (ROCK) inhibitor (IC50 values are 1.6 and 4 nM for recombinant human ROCK1 and ROCK2 respectively). Displays greater than 30-fold selectivity for ROCK against a panel of serine/threonine kinases. Induces vasorelaxation in preconstricted rat aorta (IC50 = 35 nM); lowers blood pressure in a rat model of hypertension.