The American Civil Liberties Union said in a statement that the jail had been giving ivermectin to detainees as early as November 2020. In August 2021, amid surging demand for the drug, the Centers for Disease Control and Prevention warned that ivermectin was “not authorized or approved” for any type of Covid treatment.

Misinformation that ivermectin is effective at treating or preventing coronavirus infection has run rampant across social media during the pandemic, and the inaccuracies have led some people to overdose on certain formulations of the drug, according to the F.D.A.

Dr. Karas appears to have bought into the misinformation for months, saying in an interview in August that he used the drug himself when sick with Covid. He posted as recently as Dec. 24 on his practice’s Facebook page that he was using ivermectin to treat people with Covid.