Flestolol: an ultra-short-acting beta-adrenergic blocking agent.

Flestolol (ACC-9089) is a nonselective, competitive, ultra-short-acting beta-adrenergic blocking agent, without any intrinsic sympathomimetic activity. Flestolol is metabolized by plasma esterases and has an elimination half-life of approximately 6.5 minutes. This agent was well tolerated in healthy volunteers at doses up to 100 micrograms/kg/min. In long-term infusion studies, flestolol was well tolerated at the effective beta-blocking dose (5 micrograms/kg/min) for up to seven days. Flestolol blood concentrations increased linearly with increasing dose and good correlation exists between blood concentrations of flestolol and beta-adrenergic blockade. Flestolol produced a dose-dependent attenuation of isoproterenol-induced tachycardia. Electrophysiologic and hemodynamic effects of flestolol are similar to those of other beta blockers. In contrast with other beta blockers, flestolol-induced effects reverse rapidly (within 30 minutes) following discontinuation because of its short half-life. Flestolol effectively reduced heart rate in patients with supraventricular tachyarrhythmia. In patients with unstable angina, flestolol infusion was found to be safe and effective in controlling chest pain. It is concluded that flestolol is a potent, well-tolerated, ultra-short-acting beta-adrenergic blocking agent. Use of flestolol in the critical care setting is currently undergoing investigation.