Effect of haloperidol on dopamine-induced increase in renal blood flow.

Increasing renal blood flow (RBF) by the administration of low-dose dopamine is one mechanism to increase urine output in oliguric patients. This response is mediated in part by stimulation of dopaminergic receptors in the kidney, which could be attenuated by the dopamine blocker haloperidol. We evaluated this interaction by administering both drugs in clinically used doses to six anesthetized mongrel dogs. A dopamine regimen of 2.5 micrograms/kg/min significantly increased RBF along with cardiac output and stroke volume. Simultaneous administration of haloperidol 50 micrograms/kg iv did not influence the ability of low-dose dopamine to increase RBF. Although haloperidol is an antagonist of dopaminergic receptors, the increase in RBF associated with low-dose dopamine is maintained when intravenous haloperidol is concurrently administered to dogs.