The impact of implementing a more restrictive prescription limit on Medicaid recipients. Effects on cost, therapy, and out-of-pocket expenditures.

On November 1, 1991, the Georgia Department of Medical Assistance reduced the maximum number of monthly reimbursable prescriptions from six to five. This policy change provided a natural experiment to investigate the recipient responses to a decrease in an existing prescription limit. The research design was a quasiexperimental, retrospective, 12-month interrupted time-series analysis of a cohort. The cohort consisted of 743 ambulatory recipients who were high prescription users. Complete Medicaid claims data were obtained, in addition to pharmacy-generated computer profiles for all cohort recipients to determine Medicaid and out-of-pocket prescriptions expenditures. Interrupted time-series analyses were performed to model the effect of the five-prescription limit on total, Medicaid-reimbursed, out-of-pocket, and prescription use across eight therapeutic categories. After the implementation of the five-prescription limit, total prescription use fell 6.6%, prescriptions reimbursed by Medicaid fell 9.9%, and prescriptions paid for out-of-pocket increased 9.7%. Abrupt, permanent decreases were observed for cardiovascular, miscellaneous, pulmonary, and palliative therapeutic drug categories (alpha = 0.05), whereas gastrointestinal, chemotherapy, hormone (insulin), and central nervous system prescription use remained constant. The implementation of a more restrictive prescription limit alters prescription regimens potentially predisposing elderly Medicaid recipients to clinical consequences. Further examination of the health outcomes of these recipients is necessary.