Effects of large doses of phenylbutazone administration to horses.

This study evaluates the effects of large doses of the drug phenylbutazone on horses, finding that the high dosage levels led to detrimental health effects, including a decrease in blood neutrophil count, progressive increase in serum urea nitrogen, creatinine and phosphorus concentrations, as well as gastrointestinal ulcerations, renal papillary necrosis, and vascular thromboses.

Research Objective and Methodology

• The primary aim of the research was to assess the potential health impacts of large doses of phenylbutazone administration on healthy horses.
• The drug was administered to four groupings of two horses each. Three different dosages were tested – 30 mg/kg taken orally and intravenously (IV), and 15 or 8 mg/kg given IV.
• The administered dosages were given daily, up to a duration of two weeks.

Research Findings: Health Impacts and Mortality

• All horses involved in the study exhibited symptoms of anorexia and depression following two to four treatments with phenylbutazone.
• Higher dosage levels proved to be fatal. Horses receiving 15 or 30 mg/kg doses died between the fourth and seventh days of the treatment.

Research Findings: Blood and Serum Changes

• All horses saw a decrease in their total blood neutrophil count, a key part of the immune system, more significantly in horses given the two larger dosage schedules.
• Audible increases in three constituents of the blood serum were observed – urea nitrogen, creatinine, and phosphorus, accompanied by declining serum calcium concentrations.
• Moreover, there was an observed gradual decline in the total serum protein in all eight horses.

Research Findings: Postmortem Evaluations

• The postmortem examination of the horses revealed that the primary causes of death were gastrointestinal ulcerations, renal papillary necrosis (damage to the kidney cells), and vascular thromboses (blood clots in the vessels).

Conclusion

• In conclusion, the research demonstrates that high dosage levels of the drug phenylbutazone lead to detrimental health impacts in horses, affirming its potential toxic effects when administered in large quantities, including mortality.