A prominent former pain doctor from McLean will go on trial today in federal court in Alexandria, accused of leading a broad conspiracy to traffic in prescription narcotics that prosecutors say led to the deaths of three patients.

The case against William E. Hurwitz has drawn national attention from advocates for patients with chronic pain, who decry it as a zealous attempt to criminalize what they consider good medical practice. Government officials say the prosecutions of Hurwitz and other doctors has helped stem growing abuse of OxyContin and other potent prescription painkillers.

Hurwitz, 59, is charged in a 62-count indictment that includes charges of drug trafficking resulting in death and serious bodily injury, conspiracy to traffic in controlled substances and health care fraud. Prosecutors allege that Hurwitz prescribed excessive quantities of dangerous narcotics to patients who were then selling the drugs on a lucrative black market. His dosages, they said, led to serious injuries and the three deaths.

The trial is the culmination of a two-year federal investigation into doctors, pharmacists and patients suspected of selling potent and addictive painkillers. About 50 people have been convicted. Law enforcement sources said the probe is ongoing, though Hurwitz was one of the ultimate targets.

Before he closed his practice in 2002, Hurwitz was considered a major figure in the national pain management community and was profiled on "60 Minutes.''

Prosecutors have likened Hurwitz to a "street-corner crack dealer.'' Several of his patients have been caught selling their prescriptions at exorbitant profits in other states, and the network has been blamed for fueling what authorities have called an epidemic of abuse throughout Appalachia.

But defense lawyers plan to argue that Hurwitz was only trying to help people with intractable pain and that prosecutors are over-reaching.

"This is a trophy case. They wanted a doctor,'' said Marvin D. Miller, an attorney for Hurwitz. "Doctors should decide what is appropriate medical practice, not people in law enforcement.''

The trial is expected to last six to eight weeks before U.S. District Judge Leonard D. Wexler. A 12-member jury was selected yesterday. If convicted of the most serious counts, Hurwitz, who has been free on $2 million bond, faces up to life in prison.

U.S. Attorney Paul J. McNulty declined to comment. But after the September 2003 indictment, McNulty called Hurwitz a "major and deadly drug dealer" who used the cover of medical pain management to dispense "misery and sometimes death."

Russell Portenoy, chairman of pain medicine at Beth Israel Medical Center in New York, said yesterday that pain management doctors are closely following the case. "I have a very profound concern that the appropriate way to deal with these issues is not through criminal prosecution but through an evaluation of medical practice,'' he said.

Portenoy predicted that a Hurwitz conviction would have a "strong chilling effect" on the willingness of doctors to prescribe powerful prescription narcotics, which many in the field think is the only way to relieve chronic pain. About 30 percent of Americans suffer from such pain, he said.

An attorney representing one of Hurwitz's alleged victims voiced support for the prosecution. "I don't see any other way he can be stopped,'' said Bryan Slaughter, who represents the family of Linda Lalmond. "These patients certainly do need treatment, but I don't see how Dr. Hurwitz's methods necessarily help people.''

Lalmond, 51, of North Carolina, died in Fairfax County in June 2000. In a lawsuit filed against Hurwitz, her family argued that Lalmond died two days after first meeting Hurwitz and being prescribed an excessive dose of morphine. The suit was settled last year.

Prosecutors are expected to introduce testimony about former patients of Hurwitz, in addition to taped conversations between him and his patients. The defense is expected to also call some former patients as witnesses, in addition to experts in the field of pain management.