(CNN) Doctors are increasingly being held accountable -- some even facing murder charges -- when their patients overdose on opioid painkillers they prescribed.
A Texas doctor faces charges of illegally distributing these drugs in connection with at least seven deaths, according to an indictment that was unsealed this month.
Weeks prior, a doctor in Oklahoma was charged with five counts of second-degree murder for prescribing "horrifyingly excessive amounts" of potent drugs, Oklahoma Attorney General Mike Hunter said in a statement.
In 2015, Dr. Hsiu-Ying "Lisa" Tseng became the first doctor to be convicted of murder for overprescribing painkillers. She was sentenced to 30 years to life in prison by a Los Angeles judge.
The number of doctors penalized by the US Drug Enforcement Administration has grown more than fivefold in recent years. The agency took action against 88 doctors in 2011 and 479 in 2016, according to an analysis of the National Practitioner Data Bank by Tony Yang, an associate professor of health administration and policy at George Mason University. Many other doctors have been sued in civil suits.
While high-profile cases against doctors have brought yet another spotlight to the nation's ongoing opioid epidemic, experts say this is rare and overlooks the bigger picture.
"The well-meaning doctors and dentists are the bigger part of our problem," said Dr. Andrew Kolodny, executive director of Physicians for Responsible Opioid Prescribing, an advocacy and education group. "They're inadvertently getting patients addicted, and they're also stocking homes with a highly addictive drugs."
Dr. Denise Sur remembers a time when opioids were a wonder drug, not a plague.
"In the late '80s, early '90s, we were all told that we were too cautious and we were not appropriately treating patients' pain," said Sur, a professor of family medicine at the University of California, Los Angeles.
At the same time, pharmaceutical companies aggressively marketed opioids to doctors, former Surgeon General Vivek Murthy wrote in an open letter last year. Doctors were taught that these medications were not addictive if patients were in "legitimate pain," he said. Multiple studies have shown this to be false.
"That was a quote I heard regularly," said Sur, who has testified in cases in which doctors are accused of recklessly prescribing opioids.
More and more, Sur sees other doctors referring risky patients to pain specialists who might be better equipped to offer alternative treatments, screen for addiction and, when necessary, prescribe opioids safely.
The fear, she said, "is not just strictly about being sued; it's about harming somebody."
These doctors might be looking for pain specialists like Dr. Kimberly Curseen, a palliative care doctor at Emory Healthcare who works largely with cancer patients. But even she is acutely aware of the legal precedent being set against doctors.
"Personally, it's very frightening ... when you're working with medications that are receiving this type of scrutiny," Curseen said.
But she said it's a risk that many doctors accept to help patients in need.
"This is the profession that we chose," she said.
In 2010, doctors wrote enough prescriptions for hydrocodone to give every American adult a one-month supply, according to a report by the US Centers for Disease Control and Prevention.
In general, prescription opioid abusers tend to get pills from family and friends for free. Those at the greatest risk of overdosing, however, are more likely to get the drugs through their own doctor's prescription, according to the CDC.
Another study last year found that 91% of overdose survivors were still able to get another prescription for opioids.
Some doctors may be more willing to write an opioid script than others. One study found that some emergency physicians were three times more likely to do so than other doctors at the same hospital. And their patients were more likely to be long-term users, too.
But some researchers have pushed back against the idea that a small number of doctors are responsible for the opioid epidemic.
Last year, researchers at Stanford argued that "opioid prescribing is no more skewed than other prescribing." On one hand, opioid prescriptions are concentrated among specialties like pain management and anesthesiology. These specialties have been well represented in DEA cases.
But looking more broadly, a greater number of opioid prescriptions were written by general practitioners, such as family doctors, who see far more patients overall.
Not all patients have access to pain specialists and comprehensive care in the first place, said Dr. Keith Humphreys, one of the authors of that paper and a professor of psychiatry at Stanford School of Medicine.
"There's just not that many pain medicine specialists. They can't drive national prescribing patterns," said Humphreys, also a former White House drug policy adviser under Presidents Bush and Obama.
Humphreys described criminal cases against doctors as "rare." Many doctors see these cases as outliers, which may also involve allegations of fraud, poor record-keeping and other misconduct.
But a number of doctors claim to have been falsely accused, and some of their investigations have ended in acquittals, dismissals or no charges at all.
CNN reported on the DEA investigation of Dr. Lynn Webster -- a pain specialist who was considered an expert in safely prescribing opioids -- after a string of patient deaths. In 2010, a handful of DEA agents raided his clinic, occupying "every corner of every room," he told CNN.
The investigation lasted several years, but no charges were ever brought against him.
"It's kind of like a scarlet letter that I will always carry with me," Webster said. "An investigation can be life-altering, but it can be career-ending."
The DEA has been putting more resources into investigating doctors and addressing the opioid crisis in general, according to Melvin Patterson, a DEA spokesman and agent of more than 20 years. For example, in 2015 the agency started rolling out its "360 Strategy," a program that educates doctors as part of a larger effort to fight illicit drug use in various pilot cities.
Patterson, who has investigated opioid cases involving doctors, said the DEA has made the drug epidemic a priority in recent years. He said it is much easier to push these investigations forward than before.
"There was a reluctance to really prosecute doctors" early in his career, he said. "That's being prosecuted all over the country right now. That's how far we've come."
But Patterson said that doctors shouldn't fear prescribing opioids if they're checking all the boxes. These investigations, widespread as they might be, represent a "small percentage" of doctors, he said.
"When a doctor is acting responsibly ... opioids are one of the best things they could have to treat pain," he said. "But when it's irresponsible -- in other words, a doctor hasn't even examined the patients, and they're prescribing them -- that's what's killing people."
Webster believes that "this is simply an approach to try to address the opioid crisis through legal channels" and continues to research pain therapies. He is vice president of scientific affairs at PRA Health Sciences, a company that conducts clinical research on a variety of therapeutic drugs, including opioids and opioid alternatives to pain
Webster, who has spoken in defense of other doctors in criminal cases, said that colleagues were "stunned" that this could happen to him.
"He's respected in our field," said Dr. Steven Stanos, president of the American Academy of Pain Medicine, of which Webster was past president.
Beyond legal concerns, Stanos said, doctors are acutely aware of a rising opioid death toll and powerful synthetic drugs hitting the streets, like fentanyl. Stanos said doctors are becoming "more worried" about prescribing opioids -- but that worry, he said, is not necessarily a bad thing.
"They should be careful, and opioids aren't for every patient," Stanos said. "Opioids are just a small part of (pain) management."
Doctors have been coming up with ways to avoid being put under the microscope themselves: by documenting their appointments meticulously, by following guidelines and by checking statewide prescription drug databases before taking out their pens.
Many doctors even have formal "agreements" with their patients, Stanos said. This may involve taking occasional urine samples to check for other drugs.
But experts like Stanos have had to solve another looming question: What about all the patients who were put on high-dose opioids in the past?
In the aftermath of cases involving doctors, some patients might be drug-dependent and have nowhere to go. Many face severe withdrawal symptoms and a heightened sensitivity to pain, a condition called hyperalgesia, Kolodny said. If those patients get their hands on opioids later on, they are more likely to overdose, having lost their tolerance.
Stanos, who is also the medical director of Swedish Pain Services in Seattle, has absorbed patients when nearby clinics have closed.
"We took over a number of patients that were in clinics where ... I don't agree with what was done with them," Stanos said. "Those patients are at high risk."
Stanos said doctors who receive cases like these can learn a lot from the Veterans Health Administration, part of the Department of Veterans Affairs. Early on, the health care system heavily pushed opioid painkillers as part of its pain management approach. But over much of the past decade, the VA revamped its approach to pain, offering a wider variety of pain services and addiction treatment programs.
The impact of these measures -- including the 2013 rollout of the VA's Opioid Safety Initiative -- was a major cut in the number of opioids it prescribed.
"You could call it a U-turn," Kolodny said.
"The (VA) had one of the earliest and worst guidelines on opioid prescribing that I've ever seen," he added. "And in 2017, they put out the most conservative guideline that's ever been made to date -- which is, I think, a very good guideline."
But many veterans on high-dose painkillers suddenly had to cut down medications that their bodies were dependent on.
"If you are getting a patient who's been put on chronic opioids, even though they never should've been started on it, that doesn't mean you should force them to come off rapidly," Kolodny said.
Last week, a VA-funded study found that tapering down painkillers improves quality of life for chronic pain patients. Experts say that research and guidelines on opioid use for chronic pain is otherwise lacking and that the evidence is much clearer for short-term uses -- for example, after a major surgery.
Stanos said that the VA's interdisciplinary approach to pain has changed the field but that many unaffiliated doctors aren't able to offer the same array of alternative treatments and programs.
The VA "had to deal with this even sooner than the commercial payors, Medicare and Medicaid." Stanos said. "Now, they have some of the strongest treatment centers."
It's not just doctors who have been facing legal action for the opioid epidemic. A number of states have filed suit against pharmaceutical companies for their roles in the opioid epidemic.
Even some pharmacy chains -- like Walmart, CVS and Walgreens -- have been named in lawsuits and investigations.
Missouri Senator Claire McCaskill announced on Thursday that she was expanding her opioid investigation, which focuses on the relationship between prescription drugs and the opioid epidemic. She is requesting documents from opioid distributors, which were not previously part of the investigation, and she has also added new pharmaceutical companies to the mix.
But many physicians and advocates want to focus on the doctor's office in order to protect patients at risk.
"If we're ever going to bring (the opioid epidemic) to an end ... we need these folks to prescribe much more cautiously," Kolodny said. "If you can get your patients off of opiates, that should be the goal."