Among the most shocking recent examples:

Doxycycline hyclate (100 milligrams), a widely used antibiotic, soared from $20 for 500 capsules in October 2013 to a staggering $1,849 in April 2014.





Glycopyrrolate (20 milliliters), used during surgery to prevent slowing of the heart rate, climbed from $65 for 10 vials to $1,277 during the same period.





Pravastatin sodium (10 mg), the cholesterol medication that Carol Ann Riha takes, surged from $27 to $196 for a one-year supply.

Not all generic drugs increased in price. Of the 280 generics in the PPI market basket, 73 percent decreased in price in 2013. But that leaves 27 percent that went up, in some cases into the stratosphere.

What's driving prices up

Why are some generics, including pills that have been around for decades, suddenly so expensive? In some cases, the cost of making a generic drug may increase, experts say — although that's unlikely to explain most of the recent increases. Another reason: Mergers and acquisitions in the generic drug industry have reduced the number of competitors. "One of the reasons generic drugs are inexpensive is that there is competition in the market," says Aaron Kesselheim, M.D., a Harvard Medical School expert who studies drug pricing. "When that competition goes away, prices will rise."

Between 2002 and 2013, for instance, the number of manufacturers making oral digoxin, a heart drug, fell from eight to three — and the cost soared by 637 percent. Other competitors can enter the market, of course. But it can take a year or more to get Food and Drug Administration approval to make a generic and to ramp up manufacturing. Until then, prices can remain sky high.

Price spikes or gouging?

Price spikes aren't a new phenomenon, says Stephen Schondelmeyer, an expert on drug policy and pricing at the University of Minnesota, who coauthors AARP's drug pricing reports. "We've seen drug companies raise prices before when new regulations come along. We saw it when Medicare Part D was implemented. We saw it back when Medicaid rebates were implemented. We're seeing it now partly because of the regulatory changes associated with the Affordable Care Act. Drug companies drive the prices up when they're worried about the effect of new regulations."

But some experts say the recent sharp spikes have all the earmarks of price gouging. "You'll see a particular dosage of a medication shoot up while other dosages remain the same," says David Belk, a physician in Alameda, Calif., who hosts a website called True Cost of Healthcare. "Sometimes you'll see prices spike up suddenly, stay high for a month or two, and then drop down again, for no reason." But as long as drugmakers aren't colluding in raising prices, experts say, there's nothing illegal about jacking up prices.

New drugs have always been pricey. And drug companies defend those high prices because the research and development that goes into making new medications is enormously expensive. "When a new drug is released, pharmaceutical companies can charge whatever the market will bear to recoup their R&D costs and make a profit," says Harvard's Kesselheim. "And historically, some brand-name drugmakers have steadily increased the price over time."

Because brand-name drugs reap such huge rewards, pharmaceutical companies have begun to resort to controversial ways to protect their monopoly. One strategy is to change the formula — to create a time-release version, for instance, that continues to remain under patent. Another strategy has been dubbed "pay for delay." "Essentially, brand-name drugmakers pay generics not to enter the market," explains Geoffrey Joyce, an associate professor of pharmacy at the University of Southern California who studies drug policy.

One of the most egregious examples he cites is Plavix, an anticlotting medication prescribed to prevent stroke. When the patent was challenged, the company that makes the drug agreed to pay a generic manufacturer tens of millions of dollars not to enter the market. "The brand-name drugmaker wins because they get to go on charging high prices," Joyce says. "The generic companies win because they get paid not to make a drug."