Lannett Company announced that Jerome Stevens Pharmaceutical, Inc. (JSP), Lannett's exclusive supplier, has received a letter from the Food and Drug Administration (FDA) approving the bioequivalence of its levothyroxine sodium tablet to King Pharmaceutical's Levoxyl. The product made by Jerome Stevens and distributed by Lannett, which is also sold under the brand name "Unithroid," was the first levothyroxine approved by the FDA. Levothyroxine is used to treat hypothyroidism and other thyroid disorders. It is one of the most prescribed drugs in the United States with over 13 million patients. According to market research, the annual retail sales for Levoxyl® is estimated to be approximately $344 million.