Endotoxin-induced change in hemograms, plasma enzymes, and blood chemical values in anesthetized ponies: effects of flunixin meglumine.

A study was made of flunixin meglumine (FM), an analgesic agent with antiprostaglandin activity, in the management of endotoxin-induced changes in ponies. Three groups of 5 ponies each were used: A--controls, B--nontreated ponies with endotoxin-induced shock, and C--ponies with endotoxin-induced shock treated with FM. Shock was induced in anesthetized ponies with IV injections of Escherichia coli endotoxin. Disruption of glucose homeostasis, insulin levels, hemograms, aerobic metabolism, and cell damage as indicated by plasma enzymes were observed. Treatment with FM (5 minutes) after shock was induced did not prevent general tissue damage as indicated by plasma enzymes, but separation of creatine phosphokinase into its 3 isoenzymes revealed a significant increase in the amount of the creatine phosphokinase isoenzyme bb in group B ponies, but not in FM-treated ponies (group C). The source of this isoenzyme is believed to be brain tissue. Acidosis as indicated by lactic acid and venous pH was less in FM-treated ponies than in nontreated (group B) ponies. Blood glucose and insulin concentrations changed in both groups B and C (endotoxin-induced shock), but the patterns of change were different. The only effect of FM on hematologic values was a significant decrease in blood platelet counts. The results of these experiments indicate that FM improved cellular metabolism and reduced brain damage. These effects were believed to be the result of the maintenance of mean arterial blood pressure and enhanced perfusion of vital organs by preventing extensive vasodilation in the gastrointestinal tract.