Effects of fenoldopam on renal blood flow and its function in a canine model of rhabdomyolysis

Background and objective: Our hypothesis was that fenoldopam, a selective DA₁ agonist, would protect against rhabdomyolysis-induced renal injury. Methods: We studied the effects of intravenous fenoldopam (0.1-1.0 μg kg^-1 min^-1) or saline on renal blood flow and function in 10 anaesthetized Labrador dogs in whom rhabdomyolysis and myoglobinuric acute renal failure had been induced by administration of glycerol 50% (10 mL kg^-1) intramuscularly. Haemodynamic measurements including renal blood flow and derived parameters of renal function including creatinine clearance were recorded before and for the 30 min following glycerol injection, and during the 3 h following commencement of each infusion. Serum malondialdehyde concentrations were measured before and 15 min after glycerol intramuscularly, and 30 and 150 min after commencement of the infusion. Results: In the fenoldopam group, creatinine clearance was less than placebo at 1 and 2 h after commencing the infusion (12.7 ± 11.5 versus 31.3 ± 9.9 mL min^-1, P = 0.04; 8.5 ± 5.3 versus 20.1 ± 7.4 mL min^-1, P = 0.03). A 140-fold increase in serum malondialdehyde concentration occurred in one dog (fenoldopam group). Conclusion: Fenoldopam increased the severity of the renal injury in this canine model of myoglobinuric acute renal failure.