Influence of cardiopulmonary bypass on the plasma concentrations of atenolol

Betablockers are used in the treatment of angina pectoris and others ischemic coronary diseases, reducing mortality and cardiovascular events. Atenolol is a hydrophilic betablocker which is characterized by gastrointestinal absorption, small extent of distribution and renal function-dependent elimination.

The study objective was to determine the inter-individual variability of atenolol in coronary patients.

Plasma atenolol was quantified in six blood samples collected during the preoperative period from seven patients with coronary insufficiency and surgical indication, chronically treated with atenolol PO 25 to 100 mg/day. All patients presented a normal or slightly reduced renal function.

All enrolled patients presented normal or slightly reduced renal function as a result of age and underlying disease. Atenolol plasma concentrations showed a monoexponential decline, confirming the first-order pharmacokinetics at the doses employed for the control of coronary insufficiency (mean +/- SD): 123 +/- 56, 329 +/- 96, 288 +/- 898, 258 +/- 85, 228 +/- 79 and 182 +/- 73 ng/ml at times zero, 2, 4, 6, 8 and 12h after dose administration. The investigated group showed a small inter-patient variability of atenolol administrated at multiple regimens due to the hydrophilic characteristic of the drug. Furthermore, accumulation of atenolol administered chronically was greater in coronary patients, compared to healthy subjects.

In view of its cardio-selectivity and low-variability, atenolol should be used as the first-choice drug for the treatment of acute coronary syndrome and other cardiovascular diseases.