(CNN) Three drug makers, along with an industry group, filed a lawsuit Friday to stop the Trump administration from requiring pharmaceutical companies to include their list prices in television ads.

In the suit , filed in US District Court for the District of Columbia, Merck, Eli Lilly, Amgen and the Association of National Advertisers say the rule will mislead patients about how much they have to pay for medication and that the Department of Health and Human Services overstepped its authority.

"The impetus for the lawsuit is drug prices in TV ads, but the crux of it is HHS not having the authority to mandate this action," said Eli Lilly in a statement. "Not only does the rule exceed the department's statutory authority and raise freedom of speech concerns, the focus on a medicine's list price creates confusion because it's not the price most patients will pay."

Lowering drug prices has been a central focus of President Donald Trump , as well as lawmakers on both sides of the aisle. Experts, however, have questioned the usefulness of providing the list prices of medicine in ads, as most people with insurance pay far less. They fear that advertising list prices may scare patients away from drugs they could actually afford with their health insurance coverage.

Health Secretary Alex Azar served as president of Lilly USA, the company's largest affiliate, before joining the Trump administration. He has since lambasted his former industry peers for high drug costs.

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