WASHINGTON (NEXSTAR) — The AARP says the legality of the practice of pharmaceutical companies paying to keep generic drugs off the market so they can make more money is fuzzy.

“That is a complicated question there have been a lot of legal cases about,” Leigh Purvis with AARP says.

They say brand name drugs are on average 18 times more expensive than generics.

A 2013 Supreme Court case established that the practice of paying to delay generic drugs could be a violation of antitrust laws, an illegal monopoly. AARP says these types of cases are hard to win because drug manufacturers are good at hiding the payments.

“The compensation for the generic manufacturer keeping their product off the market actually applies to a completely separate product,” Purvis says.

Now the House of Representatives is considering several bills to stop pay for delay.

The Blocking Act, introduced by Representative Shrader of Oregon and Cart of Georgia would allow additional generic drug approvals if the first manufacturer delays. A bill by California Representative Anna Eshoo would require immediate publication of every new generic drug approval to increase pressure for its release.