Local tissue damage in cows after intramuscular administration of preparations containing phenylbutazone, flunixin, ketoprofen and metamizole

Tissue irritation after intramuscular injections of 4 nonsteroidal anti-inflammatory agents was studied in 5 lactating cows. Preparations containing phenylbutazone, flunixin, metamizole (dipyrone) and ketoprofen were investigated; physiological saline was used as a control substance. Tissue reactions at the injection sites were examined by palpation and by determining serum creatine kinase. A kinetic method based on creatine kinase released from the injured muscle tissue was used, which allowed estimation of the amount of damaged muscle. The metamizole preparation clearly provoked signs of pain all the cows. After flunixin and phenylbutazone injections slight reactions were observed, and ketoprofen and saline did not cause any clinical signs. Some palpatory findings after injections were found for all the preparations except saline. Based on serum creatine kinase, the 2 most irritating preparations were the ones containing flunixin and phenylbutazone. After injections of these 2 substances, the estimated amount of damaged muscle was about 80 grams. The statistical difference between flunixin and phenylbutazone and the other 2 preparations was significant. Physiological saline had no effect on serum creatine kinase. For preparations containing phenylbutazone and flunixin, intravenous administration is recommended.