Aim: Gamithromycin, a macrolide antibiotic, is used in the treatment of bovine pasteurellosis, whereas it is used in sheep as extra-label. It is well known that macrolide antibiotics have cardiotoxic effect, however, it cannot be found the information of cardiac safety of gamithromycin in sheep in the literature. The first aim of this research was to determine the cardiac safety of gamithromycin in sheep. In addition, effects of gamithromycin on the liver and kidney functions and hemogram values were investigated.

Materials and Methods: Gamithromycin (6 mg/kg, SC) was administered as a single dose to 10 sheep. Blood samples were taken before (0. day, control) and after treatments at 0.25, 0.5, 1, 2, 3, 4, 5, 6, 7, 8 and 9 days. Serum creatine
kinease-MB mass and troponin I levels which are specific cardiac damage markers, liver, kidney damage markers and hemogram values were measured.

Results: Increased troponin I levels were determined at first day but it was not statistically significant, and there was no change determined in the creatine kinase-MB mass levels. Statistically significant (P<0.05) fluctuations were determined in the total bilirubin, total protein, creatinine and white blood cell counts, but these results were within the normal ranges.

Conclusion: It may be stated that single dose (6 mg/kg, SC) gamithromycin administration has no distinctive side effects on the heart, liver and kidney functions and hemogram values in sheep.