To amend title XVIII of the Social Security Act to provide for a Medicare prescription drug benefit.

[AI summary unavailable — showing source text] Amends title XVIII (Medicare) of the Social Security Act (SSA) to add a new part D (Voluntary Prescription Drug Benefit Program) under which each individual entitled to benefits under Medicare part A (Hospital Insurance) or enrolled under Medicare part B (Supplemental Medical Insurance) is also entitled to obtain qualified prescription drug coverage by electing to enroll: (1) in a plan that provides qualified prescription drug coverage under SSA title XVIII part C (Medicare+Choice) (M+C); or (2) in a prescription drug plan (PDP) under part D if the individual is not enrolled in a M+C plan providing qualified prescription drug coverage. Outlines standard coverage benefit packages for FY 2005. Includes for the standard package an annual deductible of $250, and requires insurers to cover 80 percent of enrollees drug costs from $251 to $1,000, then 50 percent of such costs between $1,001 and the initial coverage limit of $2,000. Requires enrollees to cover all costs between $2,001 and $4,500, and Medicare to cover the entire cost once the beneficiary has reached the $4,500 catastrophic limit. Prescribes a formula for adjustment of the deductible and thresholds for years after 2005. Est…