Dose-response relationship for the antipyretic effect of meloxicam in an endotoxin model in cats

The antipyretic efficacy of meloxicam was evaluated in a feline endotoxin model using a replicated change-over design. Twelve adult cats of both sexes were allocated at random to three experimental groups. At 30 min prior to the intravenous (i.v.) endotoxin challenge (0.5 µg/kg body weight(b.w.)), 2 animals in each group received an i.v. injection of 0.1, 0.3 or 0.5 mg meloxicam/kg b.w. and the two remaining animals in each group received physiological saline. In a second phase, 21 days later, the meloxicam/placebo treatment was exchanged within each group. The rectal temperature and scores for general demeanour were determined at 30-min intervals from before dosing to 300 min after the endotoxin challenge. Haematological parameters were analysed before and 60 min after administration of endotoxin. The results indicated a significant dose-dependent antipyretic response to meloxicam after endotoxin challenge. The antipyretic response in the medium- and high-dose meloxicam groups did not differ significantly, but both were significantly different from the low-dosage group. The individual effects of endotoxin on general demeanour were rather variable but meloxicam tended to have a beneficial effect. Endotoxin induced a reduction in the white blood cell count but this was not influenced by meloxicam. It was concluded that the pyretic endotoxin model is very suitable for studying new NSAIDs in cats and that the optimum single dose of meloxicam in this model was 0.3 mg/kg b.w.Abbreviations AUC area under the curve - b.w. body weight - i.v. intravenous - LPS lipopolysaccharide - MCV mean corpuscular volume - NSAID non-steroidal anti-inflammatory drug - WBC white blood cell count