Senator Hillary Rodham Clinton barnstormed through several upstate cities on Monday, unleashing a sharp attack on what she said was the Bush administration's failure to fix the problems plaguing a new federal drug benefit administered under Medicare.

Her criticisms, made on a swing through Syracuse, Rochester and Buffalo, seemed to reflect a growing sense among Democrats that the troubles with the new drug program are becoming a liability for Republicans as they seek to maintain control of both houses of Congress in the November elections.

In waging her attacks, Mrs. Clinton appeared at two pharmacies, a health care clinic and a hospital, arguing that low-income elderly people were paying hundreds of dollars for the same prescription drugs they paid little or nothing for before the new program started.

"Senior citizens were promised prescription drug coverage; they are now on their own," she said, speaking to a group of hospital administrators, doctors and other medical experts attending a health care forum here at Strong Hospital Medical Center.

Mrs. Clinton used a question about a controversial comment she made last week - likening the Republican-led Congress to a plantation in which dissent is not tolerated - to further her critique of the Medicare drug program and its Republican authors.

When a reporter asked her why she had made that remark, the senator explained that she was "deeply concerned" about the "heavy-handed way" in which Republican leaders ran the Congress. 

"The result is that you get bills like this," she continued, noting that one Republican architect of the new program had wound up leaving Congress to work for the drug industry. "The real corruption is that the legislation being passed is not helping people."

Told of Mrs. Clinton's overall criticisms, a White House spokesman lashed out at her, contending that her husband's administration had not produced any significant legislation to help the elderly deal with the skyrocketing costs of prescription drugs.

"The Bush administration and the Republican Congress delivered," Trent Duffy, the spokesman, said. 

Mr. Duffy went on to suggest that Mrs. Clinton was free to "go back to the bad old days when people had to choose between food or drugs."

While acknowledging problems in carrying out the program, Mr. Duffy said they were to be expected given that the program represented the biggest change to Medicare in 40 years. He said the administration was moving to address those problems.

Mrs. Clinton's trip comes as state officials around the country have confronted widespread confusion and concern among Medicaid recipients since the program was introduced on Jan. 1.

Much of that stems from the fact that many low-income people on Medicare have either been overcharged for prescription drugs at pharmacies or been denied their drugs altogether. 

Several governors - Republicans and Democrats alike - have recently announced plans to spend state money to pick up the tab for these drugs temporarily while the federal government straightens out the problems with the new program.

While Mrs. Clinton supports federal efforts to help the elderly pay for costly drugs, she has been an outspoken critic of the current program. She voted against it in 2003, arguing that it did more to help insurance and drug companies than to help the elderly. Her office has also put together a manual in English and Spanish to help constituents navigate the program's complexities. 

Mrs. Clinton and her advisers are well aware of the irony involved in her attacking Republicans for devising what has turned out to be a complicated and controversial health care plan. In the early 1990's, her plan for a national health insurance program was ridiculed by Republicans as an example of big-government excess.

Speaking at the health care forum here, she referred to her failed health care initiative, saying, "As you know, I have done a little work on health care myself and I still have the scars to show for it."

Mrs. Clinton heard directly from people with their own horror stories. "It's been a nightmare for older adults who have been frustrated and do not know what to do," said Ann Marie Cook, the president of Lifespan of Greater Rochester, an advocacy group representing the elderly.