ANNAPOLIS, Md. (AP) — A Maryland congressman says a complaint has been filed against him with a board of medical examiners for prescribing ivermectin for COVID-19.

The Baltimore Sun reports that Republican Rep. Andy Harris said in a Monday discussion about vaccine mandates by the conservative House Freedom Caucus that a complaint has been made against him.

He told The Washington Examiner that the complaint is now in the investigation stage.

The lone Republican in Maryland’s congressional delegation acknowledged in an October radio interview that he had prescribed ivermectin for COVID-19.

Ivermectin is used to treat parasites in humans but is not authorized for treating COVID-19 by the Food and Drug Administration.