WASHINGTON -- More than a month after filling thousands of unpaid prescriptions for poor, sick customers, many of America's small and independent pharmacists, particularly those in low-income and rural areas, are facing a cash crunch as they await repayment from Medicare's private drug plans.

At Rose Drugs in central Tampa, many customers are poor people with HIV infections and senior citizens on fixed incomes. When their drug coverage switched from Medicaid to Medicare on Jan. 1, store owner Rose Ferlita distributed medicines to combat their ailments even though she couldn't always verify their eligibility for the new Medicare drug benefit.

''What are you going to do?" Ferlita asked. ''My friends are my customers and my customers are my friends. You've got to give them something."

As weeks passed and the enrollment problems mounted, Ferlita took out a $40,000 loan to help pay the drug wholesalers who wanted their bills paid now, not when the hoped-for Medicare payments arrived.

''Two capsules here, three capsules there. It sounds like nothing, but when they're HIV meds, they're expensive. So I'm praying to God it's going to even out," Ferlita said.

Faced with the prospect of senior and disabled customers going without life-sustaining drugs, many pharmacists have given out tens of thousands of dollars in medication. As the bills for those drugs came in from their wholesalers, pharmacies have had to pay them while waiting for the plans to reimburse them.

''This is now getting to be one of the top levels of concern," Mark McClellan, Medicare administrator, said in testimony Thursday before the Senate Special Committee on Aging.