Karas did not immediately respond to a request for comment. A spokeswoman for the sheriff's office declined to comment. Karas has previously said no inmates were forced to take the drug.
Karas has said he began giving ivermectin at the jail in November 2020. The four inmates were given the drug after testing positive for COVID-19 in August 2021, according to the lawsuit.
The state Medical Board has been investigating complaints against Karas over the jail's use of ivermectin, and is expected to discuss the investigation at its February meeting.
In a September letter sent by his attorney, Karas told a Medical Board investigator that 254 inmates at the jail had been treated with ivermectin.
In the letter, Karas said the information given to inmates about ivermectin depended on who was administering it and that paramedics had not been given “required counseling details" to discuss with inmates about the drug. Karas said the process had since been improved.
“Since the inception of the media coverage, we adopted a more robust informed consent form to assuage any concern that any detainees were being misled or coerced into taking the medications, even though they weren't," the letter said.
The four inmates suffered side effects from taking the drug including vision issues, diarrhea and stomach cramps, according to the lawsuit.
The American Medical Association, the American Pharmacists Association and the American Society of Health-System Pharmacists last year called to an immediate end to prescribing and using the drug to treat the coronavirus.
Pharmacy prescriptions for ivermectin boomed last summer, and health officials in Arkansas and other states issued warnings after seeing a spike in poison control center calls about people taking the animal form of the drug to treat COVID-19. The CDC also sent an alert to doctors about the tend.
Despite the warnings, the drug had been touted by Republican lawmakers in Arkansas and other states as a potential treatment for COVID-19.
The inmates are asking that they receive a medical evaluation by a provider not affiliated with Karas.