Plasma pharmacokinetics of intravenous and intramuscular furosemide in the camel (Camelus dromedarius)

Single bolus intravenous (i.v.) and intramuscular (i.m.) doses of furosemide (1.5 mg kg(-1)) were administered in a crossover design to three female and three male adult, dromedary camels. Plasma furosemide concentrations were assayed by HPLC and sodium, potassium and chloride concentrations were measured using ion-selective electrodes. Plasma furosemide concentration-time plots indicated multi-compartment disposition, and there was considerable intersubject variability in the pharmacokinetic parameters. The mean (so) i.v. terminal elimination half-life was 118 (67) minutes. The systemic clearance was 5.4 (1.2) mi min(-1) kg(-1), and the steady-state volume of distribution was 0.43 (0.14) litre kg(-1). The mean absorption time after i.m. dosing was 33 (62) minutes, while the absolute bioavailability was 71 (20) per cent. The glucuronide metabolite of furosemide was not detected in plasma. Clearance was lower, volume of distribution was larger, and half-life was longer compared with published data for dogs, horses, rats and humans. Plasma potassium and sodium concentrations were significantly diminished (P<0.05) by an average of 35.6 per cent (two to six hours post-dose) and 11.3 per cent (eight hours post-dose), respectively. Plasma chloride concentrations were not significantly affected by furosemide administration.