Medicare Prescription Drug Coverage Act of 1999 - Directs the Secretary of Health and Human Services to conduct a study for a report to Congress on establishment of an outpatient prescription drug benefit under Medicare (title XVIII of the Social Security Act (SSA)) that provides for full outpatient prescription drug coverage for Medicare beneficiaries.

Amends SSA title XVIII to: (1) provide for the transfer of Federal estate tax revenues to the Federal Hospital Insurance Trust Fund under Medicare in order to offset the costs of the prescription drug benefit above; and (2) establish in the Trust Fund an expenditure account, the Outpatient Prescription Drug Account, to receive such Federal estate tax revenues, to pay for outpatient prescription drugs furnished under this Act.