WASHINGTON — A senior Republican lawmaker said Tuesday he plans to investigate spikes in the price of insulin for people with diabetes as Congress opened hearings on the high cost of prescription drugs.

“I have heard stories about people reducing their life-saving medicines, like insulin, to save money,” said Senate Finance Committee Chairman Charles Grassley, R-Iowa. “This is unacceptable and I intend to specifically get to the bottom of the insulin price increase.”

Across Capitol Hill, the House Oversight and Reform Committee held its own hearings. Chairman Elijah Cummings, D-Md., has already announced a sweeping investigation of drug industry pricing practices, sending detailed information requests to 12 major manufacturers.

Although Democrats want Medicare to directly negotiate prices and Republicans prefer free-market approaches, they seem united in their disdain for the industry’s pricing. At the White House, President Donald Trump, who once accused drugmakers of “getting away with murder,” has backed multiple regulatory actions that include approving more generic drugs and an experiment to use lower international prices to save money for Medicare.

It all adds up to a politically perilous time for a powerful industry used to setting its own terms. However, it’s still unclear whether lawmakers in the end will be able to agree on a plan of action.

The Pharmaceutical Research and Manufacturers of America points to research suggesting that price spikes of a few years ago have eased. Government price regulation will stifle innovation and deprive patients of timely access to innovative medications, the industry warns.

Insulin to treat diabetes is a particularly sensitive issue, since patients depend on the drug to try to maintain normal blood sugar and forestall complications of the disease, from heart problems to blindness and amputations. As yet there’s no effective generic competition to brand insulin costing hundreds of dollars a month.

A handful of companies dominate the insulin market, including Novo Nordisk, Sanofi and Eli Lilly, which formerly employed U.S. health secretary Alex Azar as a high-ranking executive.