Meanwhile, brand-name drug makers are raising prices at 10 percent per year.

The Trump administration has been trumpeting a huge increase in generic drug approvals by the Food and Drug Administration in the past two years, the result of its actions to streamline a cumbersome process and combat anti-competitive practices. But nearly half of those newly approved drugs aren’t being sold in the United States, Kaiser Health News has found, meaning that many patients are deriving little practical benefit from the administration’s efforts.

The administration’s aggressive push to approve more generics is designed to spur more competition with expensive brand-name drugs, and drive prices lower, President Donald Trump noted at a White House event last month. The FDA has approved more than 1,600 generic drug applications since January 2017 — about a third more than it did in the last two years of the Obama administration.

But more than 700, or about 43 percent, of those generics still weren’t on the market as of early January, a KHN data analysis of FDA and drug list price records shows. Even more noteworthy: 36 percent of generics that would be the first to compete against a branded drug are not yet for sale. That means thousands or even millions of patients have no option beyond buying branded drugs that can cost thousands of dollars per month.

“That’s shockingly high,” said former congressman Henry Waxman, who co-sponsored the 1984 law that paved the way for the generic approval process as we know it today. He said he’d like to know more, but suspects anti-competitive behavior is at least partly to blame and that revisions to the so-called Hatch-Waxman Act might be needed.

The approved generics that haven’t made it to American medicine cabinets include generic versions of expensive medicines like the blood thinner Brilinta and HIV medication Truvada. They also include six different generic versions of Nitropress, a heart failure drug, whose price spiked 310 percent in 2015.

Experts say a variety of factors are to blame. Generics sellers have fought for years against patent litigation and other delay tactics that protect brand-name drugs from competition. In recent years, vast industry consolidation has reduced the ranks of companies willing to purchase and distribute generics. And, in some cases, makers of generics obtain approvals and ultimately make a business decision to sit on them.

“It’s a real problem because we’re not getting all the expected competition,” FDA Commissioner Scott Gottlieb said in an interview, adding that it will be difficult to solve because it has so many causes. It takes five generics on the market to drive prices down to 33 percent of the original brand-name price, according to an FDA analysis.

Without generics to lower drug costs, branded manufacturers can continue to increase their prices, at a rate of roughly 10 percent a year, said Scott Knoer, chief pharmacy officer at the Cleveland Clinic. “It makes health care costs go up across the board.”

Even if hospital patients don’t directly see high drug prices in their bills, the higher costs get passed to insurers, who pass them on as higher premiums, Knoer said. They also get passed to taxpayers, who pay for drugs covered by Medicare and Medicaid.

Consolidation on multiple tiers of the drug supply chain have changed the face of the generic drug market, warping supply and demand.

In some cases, key pharmaceutical ingredients are unavailable or a manufacturer doesn’t have the capacity to launch a product because it’s having difficulty meeting demand for existing products.

Manufacturing consolidation has dramatically reduced the production of injectable drugs, which are typically administered in a doctor’s office. This may be why 157 injectable generics that were approved in the past two years haven’t been brought to market.

Erin Fox, a pharmacist at the University of Utah who tracks drug shortages, said the KHN analysis of stalled generics “highlights that companies often have a lot of products ‘on the books’ but aren’t really making them.” A few generics on the list — like dextrose 10 percent injection to treat patients with low blood sugar — would have been helpful to combat shortages the past few years. “This comes up with shortages a lot — it looks like there are more suppliers than there really are,” Fox said.

A lot can change between the time a drugmaker files a generic application with the FDA and the time it’s approved.