Adverse drug reactions in the treatment of filarial parasites: clinical reactions to diethylcarbamazine therapy in dogs infected with Dirofilaria immitis in Australia

The clinical signs associated with reactions to diethylcarbamazine therapy in dogs infected with Dirofilaria immitis include depression, vomiting and diarrhoea followed by bradycardia, softened heart sounds, weakened apex beat, low amplitude arterial pulse, pale mucosa, poor mucosal capillary refill and polypnoea. Subsequently the dogs become laterally recumbent and exhibit tachycardia and dyspnoea, with associated hepatomegaly and abdominal wall contractures. These signs are described in a group of eight reactive dogs and the possible pathophysiology, which is consistent with cardiac depression and hypovolaemic shock, is discussed.