By now, it's well-known that opioid painkillers caused an overdose epidemic that has killed tens of thousands of Americans annually in recent years. But one aspect that's understated in reports is that these painkillers failed patients, too — not just by putting them at risk of addiction and overdose but by failing to treat their pain as the drugs were supposed to.

In the Los Angeles Times, Harriet Ryan, Lisa Girion, and Scott Glover investigated a striking example of this failure: OxyContin, an opioid, doesn't live up to its promise of 12-hour pain relief for many patients. Yet Purdue Pharma, producer of OxyContin, has stood by its claim, motivated by profit even as it puts patients at risk of addiction and overdose. The Los Angeles Times reported:

• Purdue has known about the problem for decades. Even before OxyContin went on the market, clinical trials showed many patients weren't getting 12 hours of relief. Since the drug's debut in 1996, the company has been confronted with additional evidence, including complaints from doctors, reports from its own sales reps and independent research. • The company has held fast to the claim of 12-hour relief, in part to protect its revenue. OxyContin's market dominance and its high price — up to hundreds of dollars per bottle — hinge on its 12-hour duration. Without that, it offers little advantage over less expensive painkillers. • When many doctors began prescribing OxyContin at shorter intervals in the late 1990s, Purdue executives mobilized hundreds of sales reps to "refocus" physicians on 12-hour dosing. Anything shorter "needs to be nipped in the bud. NOW!!" one manager wrote to her staff. • Purdue tells doctors to prescribe stronger doses, not more frequent ones, when patients complain that OxyContin doesn't last 12 hours. That approach creates risks of its own. Research shows that the more potent the dose of an opioid such as OxyContin, the greater the possibility of overdose and death. • More than half of long-term OxyContin users are on doses that public health officials consider dangerously high, according to an analysis of nationwide prescription data conducted for The Times.

Beyond this summary, you should read the Times's investigation in its entirety. It painstakingly goes through document after document, proving Purdue Pharma executives and marketers pushed OxyContin on doctors even as growing evidence showed that it didn't work as advertised. One memo was literally titled, "$$$$$$$$$$$$$ It's Bonus Time in the Neighborhood!"

The story adds to the evidence that pharmaceutical companies misled doctors when they convinced them to prescribe painkillers in droves to treat pain. Back in the 1990s, doctors increasingly wanted to treat pain as a serious medical issue. So drug companies pushed opioids as a safe, effective way to do that — even though these drugs are not safe or, based on the Times's reporting, always effective.

Meanwhile, government regulators failed to step in even as complaints from doctors and patients piled up.

The result: Drug companies made a lot of money as people got addicted and died, and, apparently, didn't even get adequate care for their pain in many cases.

What's more, even if opioids work to treat acute, short-term pain, they won't always work for chronic, long-term pain. The evidence on whether opioid painkillers can even treat chronic pain is weak at best, but it's clear that prolonged use can result in very bad risks and complications. In other words, there's more evidence for the long-term risks than the long-term benefits.

Many people do suffer from serious pain (about 100 million deal with chronic pain in the US each year), and some of those people could benefit from painkillers. Ideally, the health care system should strike a balance between restricting these dangerous drugs and providing adequate care to patients who could really benefit.

But when doctors unscrupulously prescribe opioids, they not only put their patients at risk of addiction and overdose but also rely on a medication that might not serve the patient's needs — and perhaps overlook treatments that could help a patient. The Los Angeles Times investigation exposes just another example of how opioids have failed so many people, despite all the promises in the marketing.