Characteristics of ivermectin toxicity in patients taking veterinary and human formulations for the prevention and treatment of COVID-19.

Ivermectin toxicity developed in predominantly male patients >60 years old who ingested higher than recommended doses and developed neurologic symptoms. Patients who took a veterinary formulation of ivermectin ingested large single doses or large daily doses for several days and developed rapid onset of neurotoxicity. Patients with chronic toxicity developed milder symptoms and tended to take typical therapeutic doses, but continued therapy for weeks rather than days.