Pharmacokinetics of Famotidine in Goats (Capra aegagrus hircus) After Subcutaneous Administration

Small ruminants such as goats are susceptible to abomasal ulceration due to adverse reactions to medications, stress, and inappetence. There is limited pharmacokinetic data regarding the use of famotidine for treatment and prevention of abomasal ulceration in goats. The objective of this study is to report the pharmacokinetic parameters after a single subcutaneous administration of famotidine. Famotidine was administered at a 1.2 mg/kg dose to six healthy goats and plasma samples were collected over a 12-h period. The plasma was analyzed using reverse phase high performance liquid chromatography (HPLC) to measure famotidine concentrations. Using commercially available pharmacokinetic software, noncompartmental analysis was used to determine the pharmacokinetic parameters. The maximum plasma concentration was estimated at 735 ng/mL and the T_max was 0.64 h. The apparent terminal half-life was 1.29 h, and the mean residence time was 1.82 h. The area under the curve was found to be 1046 h*ng/mL. Five of the 6 goats in this study had been utilized for a previous intravenous famotidine investigation, and when comparing the area under the curve to this study, the range of the estimated bioavailability after subcutaneous administration was 21.43%-135%. Future research performing a pharmacodynamic study measuring the pH of the abomasal fluid could be used to determine the efficacy of famotidine on raising pH levels. Compared to other studies with intravenous administration in goats, subcutaneous administration of famotidine may be a more useful way of maintaining concentrations over time.