The three price benefit managers jointly administer 80% of all prescriptions in the U.S., the FTC said in the lawsuit.

The U.S. Federal Trade Commission sued the country's three largest pharmacy benefit managers on Friday, accusing them of steering diabetes patients towards higher priced insulin in order to reap millions of dollars in rebates from pharmaceutical companies.

The Federal Trade Commission sued on Friday the three largest pharmaceutical intermediaries charged with negotiating drug prices on behalf of insurers, claiming they are illegally maximizing profits by steering patients to high-cost insulin products.