More than 700 doctors nationwide wrote prescriptions for elderly and disabled patients in highly questionable and potentially harmful ways, according to a critical report of Medicare's drug program released today.

The review by the inspector general of the U.S. Department of Health and Human Services flags those doctors as "very extreme" in their prescribing – and says that Medicare should do more to investigate or stop them.

The study mirrors a ProPublica investigation last month that found Medicare had failed to protect patients from doctors and other health professionals who prescribed large quantities of potentially harmful, disorienting or addictive drugs.

Medicare's prescription drug program was launched in 2006 and now accounts for about one of every four drugs dispensed nationwide. Last year, the government spent $62 billion subsidizing the drugs of 32 million people.

"Strong oversight of the Medicare prescription drug program is critical for protecting patients from harm," Sen. Tom Carper, D-Del., said in an email.

Carper chairs the Senate Homeland Security and Governmental Affairs Committee, which has scheduled a hearing Monday about prescription abuse in the Medicare program, known as Part D.

The inspector general's report focused on the prescribing of nearly 87,000 general-care physicians, such as family practitioners and internists, in urban and suburban areas in 2009. These doctors accounted for about half of all the prescribing in the program that year.

The review found more than 2,200 doctors whose records stood out in one of several areas: prescriptions per patient, brand name drugs, painkillers and other addictive drugs or the number of pharmacies that dispensed their orders.

Of those, 736 were flagged as "extreme outliers." Their patterns, the report says, raised questions about whether the prescriptions were "legitimate or necessary."

For instance, 24 doctors wrote more than 400 prescriptions for at least one patient, including refills dispensed. One Ohio physician did so more than a dozen times, according to the report. The average doctor wrote 13 per patient.

In another case, an Illinois doctor had prescriptions filled by 872 pharmacies in 47 states and Guam. General-care doctors, on average, had prescriptions for all their Medicare patients filled by 52 pharmacies.

The cost to the government was enormous in some instances. Medicare paid $9.7 million for the prescriptions of one California doctor alone – that is 151 times more than the cost of an average doctor's tally, the report says.

Most of this physician's drugs were supplied by just two pharmacies, both of which had previously been identified by the inspector general as having questionable billing practices.

All told, the drugs ordered by the doctors labeled "extreme outliers" cost Medicare $352 million, the report says.

While some of this may have been appropriate, the report says, "prescribing high amounts on any of these measures may indicate that a physician is prescribing drugs which are not medically necessary or that he or she has an inappropriate incentive, such as a kickback, to order certain drugs."

Sen. Tom Coburn of Oklahoma, the ranking Republican on Carper's committee, said no one wants Medicare to tell doctors which drugs to prescribe. But the government does have a responsibility in preventing fraud and abuse, he said.

Medicare officials "should be using their data to make sure those practicing medicine are practicing medicine and not practicing a sham," said Coburn, who is also an obstetrician.

The inspector general's report calls on the Centers for Medicare and Medicaid Services (CMS), which oversees the program, to step up scrutiny of doctors with questionable prescribing patterns. It urged CMS to direct its fraud contractor to expand its analysis of prescribers and train the private insurers that administer Part D on how to spot problem prescribers.

Medicare also should send doctors report cards comparing their prescribing to their peers, the report says.

In a response to the inspector general, the Medicare agency wrote that it agreed with the recommendations, has been working to reduce overuse of narcotics and plans to expand its use of data to flag questionable prescribing.

"We must balance these efforts with ensuring that beneficiaries have access to the medicines they need," a CMS spokesman said Wednesday in a statement.

For ProPublica's investigation, reporters analyzed four years of Medicare prescription drug data and examined the prescriptions of all health professionals across specialties. It examined all prescribers – 1.7 million in 2010 alone – not just those in general-care specialties or mostly urban areas.

The new report from the inspector general is the latest to find oversight problems in Part D. Previous reports found that insurers have paid for prescriptions from doctors who were barred by Medicare or whose identities were unknown to insurers or Medicare.

Coburn said Medicare has had repeated warnings that it was failing to properly oversee the program.

"This is incompetency and lack of somebody being held accountable," he said. "It's fixable."