moxidectin and Seizures

Overdoses of macrocyclic lactones in dogs and cats can result in such signs as tremors, ataxia, seizures, coma, and blindness. Dogs with the ABCB1-1Δ gene defect are predisposed to macrocyclic lactone toxicosis at lower dosages than dogs without the defect. Intravenous lipid emulsion therapy has been suggested for treatment of macrocyclic lactone toxicosis but evidence of efficacy is limited. Initial decontamination and supportive care remain the mainstays of therapy for macrocyclic lactone toxicosis.

Topics: Animals; Anthelmintics; ATP Binding Cassette Transporter, Subfamily B, Member 1; Cat Diseases; Cats; Dog Diseases; Dogs; Fat Emulsions, Intravenous; Genotype; Ivermectin; Lactones; Macrolides; Seizures

The aim of the present study was to investigate if prolonged status epilepticus (SE), secondary to a chemoconvulsant, can induce spontaneous recurrent seizures in dogs. Clinical records at two UK referral hospitals were searched for dogs that presented in SE secondary to intoxication. Dogs were only included in the study if there was clear historical evidence of intoxication and a prolonged SE. Clinical and follow-up information was retrieved and verified by using a combination of clinical records from the two hospitals and the referring veterinarian and by contacting the owners using a telephone questionnaire. Twenty dogs met the inclusion criteria: 17 presented for metaldehyde toxicity, one for moxidectin toxicity, one for theobromine toxicity and one for mycotoxin toxicity. Of these 20 dogs, three dogs had an SE duration between 0.5 and one hour, four dogs between one and 12 hours, 10 dogs between 12 and 24 hours and three dogs greater then 24 hours. Median follow-up time for the 20 dogs was 757 days (range 66 to 1663 days). No dog had any further seizures after its SE. The present study supports the view that dogs with a prolonged SE following intoxication with the aforementioned toxins might not need long-term treatment with antiepileptic drugs after the SE has been controlled.

Topics: Acetaldehyde; Animals; Dog Diseases; Dogs; Female; Insecticides; Macrolides; Male; Molluscacides; Mycotoxins; Risk Factors; Seizures; Status Epilepticus; United Kingdom

Moxidectin is a macrolide endectocide available as a 2% equine oral gel in the US. This report presents clinical signs of moxidectin toxicosis and its treatment in equines as reported to the ASPCA Animal Poison Control Center (APCC) from January 1998 to December 2000. Nine cases of moxidectin overdose in equines occurred: 5 had signs of toxicosis such as coma, dyspnea, depression, ataxia, tremors, seizures, or weakness. The approximate dose of moxidectin at which these signs were observed ranged from 1.0 to 5.1 mg/kg. The 4 equines that ingested moxidectin between 0.9 mg/kg to 1.7 mg/kg did not show signs of toxicosis. Clinical signs were seen within 6-22 h and lasted for 36-168 h. Only 1/5 clinical equines was an adult, the others were < 4 month of age. This study supports earlier report that young foals are more susceptible to moxidectin toxicosis. All 4 equines with known outcomes recovered with treatment that included decontamination, seizure control, thermoregulation, fluid therapy, and supportive care.

Topics: Animals; Animals, Newborn; Anti-Bacterial Agents; Antinematodal Agents; Coma; Drug Overdose; Dyspnea; Female; Horse Diseases; Horses; Macrolides; Male; Retrospective Studies; Risk Factors; Seizures

A 5-month-old 22-kg (48.4-lb) sexually intact male Collie was examined after ingesting a moxidectin-containing deworming medication. The dog was comatose and had respiratory arrest after progressively worsening lethargy, ataxia, and seizures. Exposure was confirmed by isolation of moxidectin from a biopsy specimen of adipose tissue, using liquid chromatography-mass spectroscopy methods. Treatment included use of intermittent positive-pressure ventilation, activated charcoal and cathartic administered enterally, nutrients administered via nasogastric tube, and intensive supportive care. The dog was weaned from a ventilator on day 6 after ingestion and was discharged on day 10. The dog was considered clinically normal during examination 24 days after ingestion. On the basis of the dog reported here and toxicologic data provided by the manufacturer of the deworming product, some Collies may have increased susceptibility to products containing high doses of moxidectin.

Topics: Adipose Tissue; Animals; Anthelmintics; Anti-Bacterial Agents; Blood Chemical Analysis; Blood Gas Analysis; Diazepam; Dog Diseases; Dogs; Electrocardiography; Intermittent Positive-Pressure Ventilation; Macrolides; Male; Neurologic Examination; Pneumonia, Aspiration; Poisoning; Radiography, Thoracic; Respiratory Insufficiency; Seizures