WASHINGTON (NEXSTAR) — The rising cost of prescription drugs took center stage on Capitol Hill Tuesday as senators grilled legal and health experts over what some say is the source of the problem: patents.

One in four Americans say they can’t afford their prescription drugs because of skyrocketing prices, and experts say costs could double in the next decade if Congress doesn’t intervene.

Many say large pharmaceutical companies have a monopoly on drugs, arguing they’re manipulating patent law to keep cheaper generic options off the market.

“Let’s be real about what’s going on in these side deals. In the side deals, the brand company is really paying the generic to stay off the market,” Rutgers Law School Professor Michael Carrier said.

Lawmakers, Republican and Democrat alike, say it’s time to get tough with drug companies to force reform.

“It’s crap. I’m sorry. It’s horrible,” Sen. Joni Ernst, R-Iowa, said during Tuesday’s hearing. “There are Iowans who will live deciding if they’ll make a mortgage payment or a car payment or actually purchase their medication.”

“The American people are fed up,” Sen. Richard Blumenthal, D-Conn., agreed.

A panel of legal and health experts said Congress needs to do something, but James Stansel of PhRMA, which represents big drug companies, warned too much regulation could backfire.

He said the companies need to make a profit on the millions they invest in discovering new drugs. That investment, he argued, leads to “safety improvements, other things that are real improvements and we think that those things should be protected.”

Lawmakers are debating upwards of five bills tackling patent laws and pricing transparency. Sen. Dick Durbin, D-Ill., said that as hearings continue, Republicans and Democrats are inching closer to a united solution.