Effect of multiple doses of imidocarb dipropionate on renal and hepatic function of ponies

Abstract

Previous studies have shown that four intramuscular doses of imidocarb dipropionate administered at 72-hour treatment intervals are effective in sterilising experimental Babesia equi infections in horses. It has also been documented that imidocarb dipropionate has dose dependent hepato- and nephrotoxic effects in a number of species. The purpose of this study was to examine the clinical and clinicopathological effects of this multiple treatment regime of imidocarb dipropionate in healthy ponies. Specific emphasis was placed on the potential adverse effects on hepatic and renal function in this species. Serum bile acids and serum gamma glutamyltransferase activity were measured to evaluate the effect of this treatment regime on hepatic function. The diffuse hepatocellular necrosis and pronounced periportal hepatocellular swelling and degeneration previously reported as the most consistent hepatic lesions noted in equines following imidocarb treatment were not evident at the dose and dosage interval used in this study. Urinary gamma glutamyltransferase: creatinine ratios (IU/g) and fractional clearance of sodium, potassium and phosphate (%) were calculated as a measure of renal function. Urinary GGT and urinary GGT: creatinine ratios were significantly elevated on Day 5 of the trial and were considered indicative of transient changes in renal function. The rapid return to previous baseline values supported reported observations that changes between 25 and 100 IU/g may be a function of drug excretion and are not necessarily indicative of significant nephrotoxicity. It was concluded that four intramuscular treatments of imidocarb dipropionate at a dose of 4 mg/kg every 72 hours may be a relatively safe method whereby persistent Babesia equi infections can be sterilised.