Effect of some beta-adrenergic blocking drugs on the renal bloow flow in dogs

Using timed collection of blood returning via the renal veins, the renal blood flow was determined in anaesthetized dogs, following the intravenous injection of 3 beta-adrenergic blockers, namely propranolol, oxprenolol and pindolol. The test drugs were given as a bolus or as an infusion, and their effects on the renal blood flow and blood pressure were studied. All the test drugs produced diminution in both the renal blood flow and blood pressure. However, these effects were variable in degree. The diminution in the renal blood flow under the influence of beta-adrenergic blockers might be explained by concomitant reduction in the cardiac output and/or blockade of the renal vasodilator beta-adrenergic receptors. An added factor might by sympathetic stimulation with consequent renal vasoconstriction in the case of blockers with intrinsic sympathomimetic activity. Beta-adrenergic blocking drugs should be given with extreme caution in cases with impaired renal function.