Doramectin toxicity in a group of lions (Panthera leo)


  • Remo G Lobetti Bryanston Veterinary Hospital
  • Peter Caldwell Old Chapel Veterinary Clinic


Ten lions (Panthera leo) that were treated with a single injection of doramectin at a dose ranging between 0.2 mg/kg and 0.5 mg/kg showed clinical signs consistent with avermectin toxicity, namely ataxia, hallucinations, and mydriasis. Two subsequently died whereas the other eight lions recovered after 4–5 days with symptomatic therapy. Post-mortem examinations of the
two that died showed cyanosis, severe pulmonary oedema, pleural effusion, and pericardial effusion, with histopathology not revealing any abnormalities. In both these lions, doramectin brain and liver tissue concentrations were elevated. Although doramectin is regularly used in wild felids, to date there have been no reports of avermectin toxicity in the literature. This
article highlights the potential for doramectin toxicity in this species.

Author Biographies

Remo G Lobetti, Bryanston Veterinary Hospital

Bryanston Veterinary Hospital, Bryanston, South Africa

Peter Caldwell, Old Chapel Veterinary Clinic

Old Chapel Veterinary Clinic, Totiusdal, South Africa






Clinical Communication