The dramatic rise in prescription narcotics use—and the subsequent increase in overdose deaths—has led to a spate of lawsuits around the country targeting doctors for malpractice or running pill mills. But legal experts say the case of one family physician in Henderson, Nev., stands out.

Dr. Kevin Buckwalter has turned the tables, filing a lawsuit against the parents of a young woman who died from an overdose of narcotics that he prescribed.

Buckwalter's suit accuses John and Maggie DeBaun of abusing the legal process, intentionally inflicting emotional distress and interfering with his ability to do business by filing a medical malpractice case against him for the death of their daughter.

"I've never heard of such a lawsuit," said Stacey Tovino, a professor at the William S. Boyd School of Law at the University of Nevada, Las Vegas. Tovino and other Nevada legal experts said it appears to them that Buckwalter abused the legal process in an attempt to intimidate the DeBauns.

Buckwalter did not respond to a call for comment. His brother Bryce, who serves as his attorney, declined to comment about the lawsuit. In an email, he accused this reporter of harassment for attempting to contact his brother, said he would seek a restraining order and threatened to sue ProPublica.

Buckwalter has been a subject of controversy for several years. A 2008 Las Vegas Sun investigation, also by this reporter, highlighted the opinions of four pain-management specialists who reviewed Buckwalter's care of patients and said it appeared to be negligent.

Staci Voyda, a teenager addicted to prescription narcotics, wrote in her journal that she went to Buckwalter to get off drugs. But his treatment included ramping up her dosages of narcotics. She killed herself in August 2007, and family members say the drugs pushed her over the edge.

Another Buckwalter patient, 69-year-old Barbara Baile, was prescribed large doses of narcotics, which caused constipation so severe it ruptured her bowels. A subsequent infection killed her.

The DeBauns' daughter, Andrea Duncan, died in 2005 from intoxication with opiates and benzodiazepines, a class of drugs that includes Valium and Xanax. Four days earlier, her husband Clint, also a Buckwalter patient, had overdosed on prescription narcotics and died.

In a 2007 videotaped deposition for an unrelated lawsuit, Buckwalter described the treatment he provided Duncan. Under oath, Buckwalter said he did not examine Duncan on her first visit because he "did not have time," yet prescribed her 300 tablets of Xanax, an anti-anxiety medication, and the painkiller hydrocodone, a synthetic opiate.

The following year, the U.S. Drug Enforcement Administration and Nevada State Board of Medical Examiners stripped Buckwalter of his license to prescribe controlled substances. The DEA attributed at least eight overdose deaths to Buckwalter. The medical board blamed him for four cases of malpractice, including one in which the patient died. Buckwalter closed his practice.

Dallas lawyer Kay Van Wey, who specializes in pill mill cases, filed six lawsuits against Buckwalter on behalf of patients who died or were harmed. The DeBaun case was filed in April 2009, past the statute of limitations in Nevada. But Van Wey argued in the complaint that the deadline should be extended because Buckwalter allegedly concealed his negligence and altered medical records.

A judge didn't buy the argument and dismissed the case. Buckwalter claims in his lawsuit that the DeBauns sued to harass and annoy him.

Buckwalter has denied all of the allegations that he provided substandard care. His lawsuit against the medical board to get his prescribing privileges reinstated was unsuccessful.

Jeffrey Stempel, a professor at the UNLV law school, said that for the DeBauns' lawsuit to be considered an "abuse" of the legal process, there would have to be some ulterior motive other than seeking damages for their daughter's death.

Ann McGinley, another professor at the UNLV law school, said it takes more than simply filing a lawsuit to support a claim of intentional infliction of emotional distress. And given that Buckwalter lost his ability to prescribe controlled substances in 2008, it's difficult to see how the DeBauns interfered with Buckwalter's ability to conduct his business, she said.

McGinley said that if lawsuits like Buckwalter's became more common, they could have a chilling effect, discouraging patients from pursuing legitimate malpractice claims. "My concern is that other doctors will take this on as something that they will do regularly," she said.