Ultra-short-acting beta-blockade: a comparison with conventional beta-blockade.

Area of Science:

• Pharmacology
• Cardiovascular Medicine

Background:

• Esmolol is a beta 1-selective adrenoceptor antagonist metabolized by esterases.
• Its pharmacokinetic and pharmacodynamic properties require comparison with traditional beta-blockers like propranolol.

Purpose of the Study:

• To compare the beta-receptor and hemodynamic effects of esmolol with oral and intravenous propranolol.
• To evaluate the onset and offset of beta-blockade induced by esmolol.

Main Methods:

• A study involving 12 healthy men.
• Administration of esmolol infusions and propranolol (oral and intravenous).
• Measurement of beta-receptor blockade and hemodynamic parameters, including isoproterenol and exercise-induced tachycardia, and blood pressure.

Main Results:

• Esmolol achieved 90% steady-state beta-blockade within 5 minutes.
• Beta-blockade from esmolol dissipated within 18-30 minutes, while propranolol's blockade persisted.
• Esmolol demonstrated significant hypotensive effects, reducing systolic blood pressure by 20 mm Hg at high doses.

Conclusions:

• Esmolol is a potent beta 1-selective antagonist with a rapid onset and offset of action.
• Its pronounced hypotensive effect suggests utility in hemodynamically unstable patients and hypertensive emergencies.