Naftopidil

Naftopidil (Flivas) is a selective α1-adrenergic receptor antagonist or alpha blocker with a Ki of 58.3 nM. Naftopidil (Flivas) is an antihypertensive agent. Naftopidil (Flivas) binds specifically to alpha 1-adrenoceptors. The Ki values are 58.3 nM for naftopidil, 0.43 nM for prazosin, and 197 nM for urapidil. The affinities of naftopidil to alpha 2- and beta-adrenoceptor sites are very low (> 6,000 and > 2,500 nM). Naftopidil relaxes aortic strips precontracted with norepinephrine concentration-dependently, and naftopidil (Flivas) shifts the concentration-response curve of norepinephrine in a parallel manner to the right. The pA2 values are 7.10 for naftopidil, 8.85 for prazosin, and 6.25 for urapidil.