Democrats have long supported two proposals that Mr. Trump endorsed during the 2016 presidential campaign. The government, they say, should directly negotiate with drug manufacturers to obtain lower prices for Medicare beneficiaries. And consumers, they say, should be allowed to import pills from Canada and certain other developed countries where brand-name drugs often cost less.

In a speech on Monday, the secretary of health and human services dismissed those solutions, which Mr. Trump backed away from when he announced his plan on Friday, as quack remedies.

“The only way that direct negotiation could possibly save money is by doing something this administration doesn’t believe in: denying access to certain medicines for all Medicare beneficiaries through rationing, or setting prices for drugs by government fiat,” said the secretary, Alex M. Azar II. “We don’t believe either of these proposals would put American patients first. They would move us toward the kind of socialized medicine systems that have such a notorious reputation for poor quality and access.”