A controlled study was performed to determine the potential
toxic effects of the new nonsteroidal anti-inflammatory drug, eltenac
(4-[(2,6-dichlorophenyl) amino]-3-thiopheneacetic acid), in horses.
Four treatment groups were formed, each composed of 6 horses. The
drug was injected intravenously, once daily, at a dose rate of 0.5
mg/kg, 1.5mg/kg or 2.5 mg/kg for 15 days. A control group was
injected with sterile saline solution. Parameters assessed were hay
and water consumption, daily clinical observations (evaluation of
attitude, mentation, pulse and respiratory rate, fecal consistency,
skin condition, and color and hydration of mucous membranes),
physical examinations, complete hemogram, coagulation profiles,
serum biochemical profiles, urinalysis, gastroscopic examinations and
gross post-mortem and histopathological examinations on all organ
systems. All examiners were blinded to group assignment and
dosage levels until the completion of the study. A few glandular
gastric ulcers, mild in severity, developed in seven animals during
the treatment period. This occurred more often in horses treated
with high doses of eltenac (P=.02). A dose dependent change of WBC
count and neutrophil count were noted. Total protein, albumin and
globulin levels had dose dependent decreases. One horse in the high
dose group (2.5mg/kg) developed ventral edema as well as
hypoproteinemia. N one of the horses in any of the dosage groups
exhibited depression or anorexia. Gross post-mortem and histologic
examination did not reveal any signs of drug related gastrointestinal,
renal or hepatic abnormalities. Minimal toxic effects of eltenac given
intravenously were greatest in horses treated with 2.5 mg/kg of the
compound for 15 days.