The District of Columbia agency that takes disciplinary action against doctors was unaware for five years that Vice President Cheney's personal internist was under treatment for an alleged addiction to prescription drugs because of a confidentiality agreement the agency maintains with a physicians group, officials involved said yesterday.

Until informed by a reporter last week, the District's Board of Medicine, which investigates allegations of physician wrongdoing, did not know that George Washington University Medical Center had referred Gary Malakoff, the director of its internal medicine division, for treatment in 1999.

The licensing board was not notified by the Medical Society of the District of Columbia, the physicians professional group that for years oversaw Malakoff's unsuccessful treatment while he continued to treat patients. The two organizations maintain an agreement, hammered out in recent years, that emphasizes the privacy rights of impaired doctors while they are being treated as patients.

Under the terms of that agreement, the society will not tell the board that a local physician has a drug, alcohol or other problem as long as that physician stays in counseling for five years, undergoes scheduled drug tests if appropriate and agrees to stop seeing patients if those terms are broken.

Nor was George Washington required to notify the board about Malakoff. Only when a complaint is filed alleging harm to a patient, or when a medical center invokes disciplinary action lasting more than 30 days, is the Board of Medicine automatically notified.

Even the institution making the referral can be left in the dark.

"Once we do the reporting to the Medical Society, that's the last we hear about it," said GWU Provost John Williams, who was among those informed of the problem in 1999 and was involved in Malakoff's referral to the D.C. Medical Society. "The person becomes a patient, and they can't even tell me what's happening."

Over the past four years, Malakoff has repeatedly attested to the excellent health enjoyed by the vice president, a survivor of four heart attacks, and continued to be part of his medical team. He was placed on leave in May when the Medical Society informed George Washington that Malakoff's treatment was failing and that he should no longer see patients, said Alan Wasserman, chief of the medical center's department of medicine and Malakoff's immediate supervisor.

Wasserman said he made the decision to place Malakoff on "indefinite leave." Malakoff will remain on leave until the Medical Society confirms that he is fit to practice, Wasserman said.

Attempts to reach Malakoff for comment yesterday were unsuccessful. Kevin Kellems, a spokesman for Cheney, declined yesterday to say how long the vice president had been aware of Malakoff's struggle. Kellems confirmed that Malakoff was no longer on Cheney's personal medical team, as the New Yorker first reported Sunday.

Even after Malakoff was placed on leave, under the terms of the agreement between the Medical Society and the licensing board, the board was not notified because Malakoff agreed to stop seeing patients.

"The argument is that by keeping it all secret, the Medical Society will be more likely to get physicians to come forward and enter these programs," said Sidney M. Wolfe, director of Public Citizen's Health Research Group. Although that strategy has some merit, Wolfe said, "it's fairly risky. It's really a dangerous situation for the public."

In some cases, said James Granger, the medical board's executive director, drug-abusing doctors are allowed to retain their Drug Enforcement Administration prescribing privileges if it is determined that removal of those privileges might compromise their ability to maintain their medical practices. Those privileges give the physicians the ability to write prescriptions for especially potent and addictive narcotics.

Malakoff was allowed to keep his DEA number, Wasserman said.

Wolfe has long advocated stricter oversight of impaired doctors and has been particularly critical of the D.C. medical licensing board, which ranks among the nation's lowest in terms of the percentage of doctors disciplined each year.

Full disclosure of a doctor's impairment record is but one of several issues raised by the revelations. Another is the apparent ease with which the doctor was able to keep obtaining strictly controlled drugs known for their addictive potential. The New Yorker, citing divorce records and other documents, said that Malakoff wrote several prescriptions to himself using other doctors' names and DEA numbers.

According to the New Yorker, the papers also document his purchase of tens of thousands of dollars' worth of controlled substances over the Internet, including a nasal spray version of Stadol, a powerful pain killer whose addictive powers have prompted some lawyers to advertise for patients seeking to sue the drug's maker.

Also at issue is whether drug tests administered as a routine part of the Medical Society program failed to pick up Malakoff's alleged ongoing drug use. Some people involved in drug treatment programs have managed to manipulate drug test results, using any number of kits available on the Internet. It remained unclear yesterday whether Malakoff was still taking drug tests or why the Medical Society had concluded that his treatment was a failure.

That determination forced Malakoff to choose between agreeing to stop seeing patients or having his case referred to the licensing board.

Almost as soon as Bush selected Cheney to be his vice presidential running mate July 25, 2000, questions arose about Cheney's medical history, which included three heart attacks in the 1970s and 1980s, heart surgery, high cholesterol and gout. Malakoff, who had been Cheney's primary care physician since 1995, spoke up to assuage those concerns.

"At this time, Mr. Cheney is in excellent health," Malakoff said then. "I monitor him closely for his known medical problems. He is up to the task of the most sensitive public office."

By that time, Malakoff was already in treatment for drug addiction.

Malakoff saw Cheney on Nov. 29, 2000, for a routine medical follow-up after his treatment for what doctors called a "minor heart attack" -- his fourth -- seven days earlier. "We told Mr. Cheney he can resume his usual schedule and stressed the importance of good exercise and nutrition," Malakoff announced that day.

Williams, the George Washington provost, said yesterday that he, too, was a patient of Malakoff's and had not noticed evidence of impairment during his visits in recent years. "Was he taking just enough to take the edge off?" Williams asked. "Did he take it every day? I still do not even know what he was taking."

Williams said that some types of doctors, notably anesthesiologists, of which he is one, are especially at risk of becoming addicted to prescription drugs, while internal medicine, which Malakoff practiced, is "not considered a high-risk specialty."

Staff writer Cheryl W. Thompson and researcher Meg Smith contributed to this report.