By Shelley Childers abc13 KTRK Houston

 Ivermectin was developed to treat parasites in both humans and animals.

It’s an FDA-approved drug for that specific purpose at a very specific dose, but for more than a year, Dr. Joseph Varon said he has proudly been using it, off-label, to treat thousands of COVID-19 patients admitted to United Memorial Medical Center.

“I have used Ivermectin in a few thousand patients,” he said. “I cannot tell you the exact number, but I know that it’s been quite a large number of patients and I have not seen a single significant side-effect. Not one,” said Varon.

He and his colleagues began touting the drug last December, holding a press conference to implore the medical community to use it as part of COVID-19 treatment.

But a recent surge on animal feed stores, where the drug is sold as a de-wormer for cows and horses, has the FDA sending out a warning, saying Ivermectin should not be used to treat or prevent coronavirus.

It is not approved for that use.

READ MORE: Horse dewormer as a COVID treatment puzzles pet stores