About 536,000 low-income Medicare beneficiaries are without access to discounts on popular medicines after Pfizer ended its discount card use yesterday, according to The New York Post. Headquartered in New York City, Pfizer is the nation’s largest pharmaceutical company.

Although the company had alerted cardholders for months that the program would end Aug. 31, the replacement Medicare discount card program has proved confusing for the nation’s 40 million Medicare beneficiaries. Only 4.1 million have signed up, according to the Times.

While the new Medicare-approved discount cards will tide over savvy consumers until prescription drugs become a standard part of Medicare benefits in 2006, advocates stress that the neediest and sickest now are the most likely to be confused by the new program.