Acepromazine maleate is a catecholamine blocker that causes arterial hypotension via vasodilatation and is commonly used as a preanesthetic sedative in dogs. It also prevents epinephrine-induced arrhythmia and ventricular fibrillation under halothane. It decreases respiratory rate without notable alterations in pulmonary gas exchange and acid-base balance, but it also causes hypothermia and decreases packed cell volume and hemoglobin concentration through storage of blood in the spleen. In this study, six healthy beagles were given either acepromazine or saline while under anesthesia (thiopentone and isoflurane-no surgery was performed) to investigate whether the peripheral vasodilatation caused by acepromazine provided protection of renal function. Blood gases and circulatory and ventilatory variables were monitored, and renal function was evaluated by scintigraphic measurement of glomerular filtration rate (GFR), relative renal blood flow, and analyses of urine. Results in dogs treated with acepromazine showed high values of relative renal blood flow despite low blood pressures (mean ± SD arterial blood pressure, 66 ± 8 mm Hg) during anesthesia, which is below the threshold (80 mm Hg) for autoregulation of GFR. Mean arterial blood pressure after administration of saline was significantly higher (87 ± 13 mm Hg); however, there was no significant difference between GFR, relative renal blood flow, or other renal function indices in the two groups, suggesting that renal function is protected despite reduction in blood pressure.

COMMENTARY: Despite these results, it should be noted that experience with combinations of acepromazine and perioperative nonsteroidal antiinflammatory drugs can induce acute renal failure in dogs anesthetized for ovariohysterectomy. Therefore, care should be exercised when acepromazine is used as a preanesthetic in combination with drugs that may negatively affect renal hemodynamics.

Effects of acepromazine on renal function in anesthetized dogs. Boström I, Nyman G, Kampa N, Häggström J, Lord P. AM J VET RES 64:590-598, 2003.