Prevention of adverse reactions following milbemycin D administration to microfilaremic dogs infected with Dirofilaria immitis.

Abstract

Some adverse reactions such as shock-like reaction and dirofilarial hemoglobinuria (caval syndrome) occasionally occurred in microfilaremic dogs following milbemycin D (Milbe) administration. This study was carried out to seek the prevention of these adverse reactions. In two groups containing 16 and 9 dogs respectively which were administered either chlorpheniramine maleate (1 mg/kg) or indomethacin (2.5 mg/kg) simultaneously with Milbe (1 mg/kg), the incidence of clinical signs such as the pale color of the visible mucous membranes, respiratory disorders, caval syndrome and shock-like reaction as well as changes in clinical parameters such as RBC and WBC counts, WBC profile and serum total protein, were almost equal to that observed in the group administered Milbe alone. In 41 dogs administered prednisolone (1 mg/kg) simultaneously with Milbe (1 mg/kg), no shock-like reaction was observed. Changes in clinical parameters were different from those in the group administered Milbe alone, whereas some clinical signs of adverse reactions, including caval syndrome, were observed. These results indicated that prednisolone was effective for prevention of the shock-like reaction in microfilaremic dogs induced by Milbe.