The elimination of selected drug products from the Michigan Medicaid formulary: a case study.

The purpose of this study was to evaluate the prescribing behavior, recipient response, and economic impact of the removal of selected prescription drug products from the Michigan Medicaid formulary. The frequency with which alternate legend drugs were prescribed and the frequency of continuous therapy via out-of-pocket cash were determined. From 17 independent Michigan pharmacies, a total of 137 patients with prescriptions for at least one eliminated drug product was identified. Of the Medicaid recipients on continuous therapy, 46% discontinued therapy. Over 23% had an alternate legend drug prescribed still covered under the Medicaid drug benefit. The alternate drug resulted in significantly higher acquisition costs. Over 30% of the recipients continued therapy at their own expense, representing a cost savings to the Medicaid program.