Hemodynamic characterization of bufuralol-HCl and pindolol based on the competitive effects of isoproterenol.

In this hemodynamic study a new beta-receptor blocker, Bufuralol-hydrochloride was compared with Pindolol under an Isoproterenol infusion with increasing doses in healthy male volunteers. We found the following results: 1. Before Isoproterenol peripheral resistance increased after acute i.v. application of Pindolol but decreased after Bufuralol-hydrochloride i.v. application. 2. After beta-receptor blockade with either Bufuralol-hydrochloride or with Pindolol a shift to the right of the dose effect relationship concerning heart rate and cardiac output under Isoproterenol infusion was observed, indicating beta 1-blockade. 3. The reduction of peripheral resistance which is usually observed as a sign of beta 2-blockade was also shifted to the right under the influence of both drugs. 4. This proves Bufuralol-hydrochloride to be a non-specific beta-blocking agent with an affinity to the beta 1- and beta 2-receptors. 5. Although Bufuralol-hydrochloride has a beta 2-blocking property which is even more pronounced than that of Pindolol, it reduces acutely, intravenously given, peripheral resistance.