Washington ? The landmark Medicare bill approved Tuesday by the Senate will transform the way senior citizens pay for their prescription drugs, initially lowering their costs and eventually changing how they get their health care for decades to come.

Beginning in April or May, seniors can expect to see lower drug prices with a prescription drug card, giving them discounts of approximately 10 percent to 25 percent. According to executives at Walgreens, the average monthly retail price of a 30-day supply of the cholesterol drug Lipitor is $77 for a 10-milligram dose, for example, and the discount card would knock that price down to anywhere from $58 to $69.

The legislation, which President Bush plans to sign after the Thanksgiving holiday, will provide prescription drug coverage to 40 million seniors and people with disabilities.

The Senate voted 54-44 in favor of the measure, the first major expansion of the Medicare program since it was created 38 years ago, following its passage in a bitterly close House vote early Saturday.

“Today is an extraordinary day,” proclaimed Senate Majority Leader Bill Frist, R-Tenn., saying the plan unleashes the combined forces of the public and private sectors to deliver drugs and health care. “Today is a fateful day.”

But Democrats — who said a greater role for private insurers and pharmaceutical companies could undermine Medicare — insisted seniors would render the ultimate verdict.

‘Debate is not over’

Senate Minority Leader Tom Daschle, D-S.D., almost immediately introduced legislation to repeal several of the most controversial aspects of the bill, as well as to allow seniors to import drugs from Canada and Western Europe. “This debate is not over,” he said.

The new prescription drug cards will only stay in effect until 2006, when the long-term program kicks in.

Under that plan, senior citizens will be able to enroll in a prescription drug plan under Medicare or take out a private insurance policy that offers drug coverage.

For low-income seniors, all premiums and deductibles would be waived if their earnings do not exceed $12,123 a year, and there would be no coverage gap. Medicaid recipients with incomes at the poverty level would obtain their prescription drugs through the new Medicare program, paying $1 for generic drugs and $3 for brand-name medicines.

While the discount drug card is expected to save seniors money on their prescriptions, firms providing comprehensive drug coverage have had little success over the years reining in costs for consumers. By many estimates, employers and private health plans’ drug costs are rising 15 percent annually.

The legislation would allow drug plan administrators to restructure the benefit as they like, although the deductible could not be changed. For example, companies could decide to charge higher premiums but minimize the gap in coverage.

“For older seniors who aren’t really part of a current employer or company-sponsored health plan, this is going to be a new learning experience for them,” said Todd Swim, a health benefits analyst with the Chicago office of Mercer Human Resource Consulting.