Pharmacokinetics of esmolol in anesthetized patients receiving chronic beta blocker therapy

The pharmacokinetics of esmolol, a new, ultra-short-acting beta adrenergic blocking drug, were studied in 19 patients undergoing coronary artery surgery. Esmolol was administered as a continuous infusion, and blood concentrations were measured at intervals up to 40 min after discontinuation of the infusion. In all patients, a bi-exponential equation best described the esmolol concentration--time curve. Half-lives for the distribution and elimination phases were 1.34 +/- 0.77 min and 9.9 +/- 4.55 min (mean +/- SD), respectively. The mean values for V beta and V epsilon were 1.9 +/- 1.24 l X kg-1 and 0.41 +/- 0.31 l X kg-1, respectively, and the total clearance was 128 +/- 41 ml X kg-1 X min-1.