Medicaid Prescription Drug Fair Access and Pricing Act of 1990

Medicaid Prescription Drug Fair Access and Pricing Act of 1990 - Amends title XIX (Medicaid) of the Social Security Act to condition Medicaid coverage of outpatient drugs provided by a manufacturer upon such manufacturer providing a quarterly rebate to each State Medicaid agency so that such agencies end up spending no more for single source and innovator multiple source drugs than the best price charged other customers and recover, for the purchase of other covered drugs, ten percent of the amount charged retail pharmacies and wholesalers for such drugs. Sets the best price at the lower of the best price in the marketplace when the drug is dispensed or the best price in the marketplace as of September 1, 1990, indexed to the consumer price index. Sets a floor and ceiling on manufacturer rebates.

Authorizes a physician to obtain prior Medicaid approval to dispense a single source or innovator multiple source drug that is not subject to a rebate. Requires Medicaid prior approval programs to operate 24 hours a day and provide an immediate response to a physician's inquiry.

Requires each State to develop a drug review program, by January 1, 1993, to assure that prescriptions are appropriate, medically necessary, and unlikely to result in adverse medical results. Includes prospective and retrospective drug prescription review and physician and pharmacist education in such program. Provides enhanced Federal funding of the cost of such programs.

Provides that this Act does not require States to provide Medicaid coverage for the covered outpatient drugs of a manufacturer which requires, as a condition for the purchase of such drugs, that the manufacturer be paid for associated services or tests provided only by the manufacturer or its designee.

Directs the Secretary of Health and Human Services to conduct a study on the therapeutic interchangeability of drugs.