TRENTON, N.J. — Hillary Clinton was among the patients and politicians who voiced outrage this week after it became public that the price of a 62-year-old drug used to treat a life-threatening infection had been raised by more than 5,000 percent.

But exorbitant drug price hikes like that have happened increasingly over the last few years. And they could become even more common because of decreasing competition in the pharmaceutical industry, among other factors.

The issue was brought to light after a Sunday article on drug price increases by The New York Times.

The story featured Turing Pharmaceuticals, a startup that paid Impax Laboratories $55 million in August for rights to Daraprim. It’s the only approved treatment for a rare parasitic infection called toxoplasmosis that mainly strikes pregnant women, cancer patients and AIDS patients. Turing’s CEO, former hedge fund manager Martin Shkreli, soon raised Daraprim’s price from $13.50 to $750 per pill.

The increase evoked outrage among patients and industry groups. Hillary Clinton, a Democratic presidential candidate, called the move “price gouging,” and then released proposals to address some aspects of rising drug prices.

After the public outcry, Shkreli said he would reduce the price of Daraprim. A Turing spokesman told The Associated Press on Wednesday that Turing is committed to “a serious price adjustment,” but hasn’t decided how much or set a timetable.

But rising drug prices are likely to remain an issue. For many generic drugs, industry consolidation has left only one or two companies making a particular medicine. That’s led to lengthy shortages for an increasing number of crucial medicines, driving up prices, particularly for drugs for infections, blood pressure and seizures.

The Turing case highlights a recent trend in which a drugmaker buys a smaller one or just its rights to an old brand-name drug, intending to sharply increase the price, said Dr. Peter Bach, director of the Center for Health Policy and Outcomes at Memorial Sloan-Kettering Cancer Center.

He said this works only when the drug is essential, there’s little or no competition and no good alternative medicine, and the number of potential patients is too small for a rival to spend years and millions of dollars to get Food and Drug Administration approval to sell the drug.