Pharmacokinetics of sulphadimethoxine in cattle

Four healthy Angus steers received a single rapid intravenous injection of sulphadimethoxine at a dose of approximately 55 mg/kg. The elimination half-life determined from plasma concentration-time data was approximately 12-5 h, and the volume of distribution was 31-0 per cent of body weight. Animals also received sulphadimethoxine intravenously or orally at a loading dose of approximately 55 mg/kg, followed by sustaining oral doses of approximately 27-5 mg/kg at 24, 48 and 72 h. It was demonstrated that oral maintenance doses served to sustain sulphonamide plasma concentrations achieved with the loading dose.