Lipid-infusion therapy of avermectin-induced neurotoxicosis in two dogs with homozygous nt230(del4) MDR1 mutation

Lipid-infusion therapy of avermectin-induced neurotoxicosis in two dogs with homozygous nt230(del4) MDR1 mutation Avermectins can provoke life-threatening neurotoxicosis in MDR1-mutant dogs due to their highly increased permeability across the blood-brain barrier in the absence of MDR1. Therapeutic options are still limited; therefore, we decided to treat this type of intoxication in two dogs using lipid infusion. The two dogs with homozygous nt230(del4) MDR1 mutation were presented with neurological symptoms. An 11-year-old Smooth Collie had received 1 mg/kg doramectin by subcutaneous injection. Based on the high dosage, a poor outcome was assumed. Secondly, a 5-year-old Australian Shepherd had ingested ivermectin vermicide paste licensed for use in horses. Initially, the dog showed mild ataxia, but its depression dramatically increased within 24 hours. In both cases, a 10% lipid infusion was used as a new treatment option, with a daily bolus infusion of 4 ml/kg over 60 minutes followed by infusion of 1.5-2.0 ml/kg/h over four hours for five days. Both dogs showed continuous improvement after lipid infusion and were discharged without any remaining symptoms of neurotoxicosis. Although we cannot definitely exclude that in both dogs the improvement and outcome would have been the same without lipid infusion, based on our clinical experience with such intoxications, both dogs seemed to benefit from the lipid infusion scheme used in terms of accelerated improvement and positive outcome. As no severe adverse effects are to be expected from repeated lipid infusion and no specific treatment is available for avermectin-induced intoxications, lipid infusion can be recommended as a new treatment option.