WASHINGTON — Oregon Democrats are criticizing Republican Sen. Gordon Smith for voting against an effort by Democratic Sen. Ron Wyden to give the government power to negotiate Medicare drug prices directly with pharmaceutical companies.

Smith voted against the amendment last week as part of a budget-cutting package.

Wyden, who has been pushing for the Medicare provision since last year, criticized senators who opposed his amendment, saying they were “keeping us from doing the right thing for our seniors.”

The 2003 Medicare reform law — which takes effect in January — bars Medicare administrators from interfering with negotiations between Medicare recipients and hospitals, drug manufacturers, wholesalers or suppliers. Wyden voted for the law but has vowed to change it, starting with the plan to grant bargaining power for drug prices.

Wyden, who frequently works with Smith despite their partisan and philosophical difference, did not criticize his Oregon colleague.

But in a blistering speech on the Senate floor, he said opponents were making it harder to negotiate lower Medicare drug prices.

“What the federal government would be doing — unless the Congress steps in — is pretty much like somebody going to Costco and buying toilet paper one roll at a time,” Wyden said on the Senate floor. “The federal government isn’t using its bargaining power to hold down the costs of medicine. At a time when prescriptions are one of the fastest-growing forces in American health care, that just defies common sense.”

Wyden’s amendment, which he co-sponsored with Sen. Olympia Snowe, R-Maine, won 51 votes on Thursday, but was defeated because of a procedural rule requiring 60 votes for passage.

Spokesman Chris Matthews said Smith shared Wyden’s concerns about drug prices, but opposed the amendment because he was concerned it could have helped prevent the underlying bill from passing.

Smith, a member of the Senate Finance Committee, had helped negotiate the budget package, including protections for Medicaid recipients that Smith says could have been harmed by a plan originally proposed by GOP leaders.

The Senate bill is estimated to trim $36 billion, or 2 percent, from budget deficits forecast at $1.6 trillion over five years. Smith said Medicare and Medicaid savings in the bill would be squeezed from drug company and pharmacy profits and should have minimal effect on Oregon residents.

Matthews said Smith, a leading GOP moderate, “had committed (to Senate leaders) to basically supporting the (overall) bill without any major changes.”

Kelly Steele, a spokesman for Oregon Democrats, said Smith’s vote shows that he “continues to side with the big drug lobbyists that fund his special interest vacations — at the expense of lower prescription drug costs for all Oregonians.”