PHARMACOKINETICS AND CLINICAL EFFECTS OF A SINGLE ORAL DOSE OF TRAZODONE IN THE DOMESTIC GOAT (CAPRA HIRCUS) AS A MODEL FOR WILD RUMINANTS.

Abstract

Trazodone is an antianxiety medication commonly used in human and veterinary medicine. Stress-related trauma is the leading cause of morbidity and mortality in wild ruminant species. Trazodone could reduce stress and allow safer capture and handling, thus having a positive effect on their welfare. The objective of this study was to describe the clinical effects and pharmacokinetic profile of an oral dose of trazodone in domestic goats (Capra hircus) as a model for wild ruminants. A pilot study using ethograms and accelerometers identified an oral dose of 10 mg/kg as optimal to reduce activity levels. This dose resulted in a 502% increase in time spent sleeping (P=0.0016) and a 623% increase in time spent lying down (P=0.01). Additionally, there were reductions of 72% in time spent grooming (P=0.02), 49% in time spent moving (P=0.01), and 87% in time spent observing (P=0.0002). Activity levels were significantly decreased by 31% for 4 hr following administration (P=0.049). There were no observed adverse effects. Time spent eating or ruminating was not affected by trazodone administration (P > 0.05). The pharmacokinetics of trazodone following a single oral dose of 10 mg/kg in 7 goats was assessed. All animals achieved plasma concentrations over 130 ng/ml, a level considered therapeutic in humans and dogs, for a mean of 6.4 ± 5.0 hr. Mean terminal half-life was 10.55 ± 6.80 hr. All goats achieved maximum concentration within 5-15 min and still had detectable plasma levels at 24 hr. Trazodone appears promising to decrease stress in exotic ruminant species. Further research is warranted to establish its efficacy in other ruminant species and clinical situations.