title: The differential impact of copayment on drug use in a Medicaid population.
abstract: In this study of the influence of copayment on drug utilization, we examined the prescription experience of 10 categories of drugs used by Medicaid beneficiaries in South Carolina over a four-year period. We observed an immediate and significant effect of copayment on the level of expenditures for all drug categories except analgesics and sedative/hypnotic drugs. The impact of copayment on the changes in the slopes of the series was not as dramatic. Only expenditures for cardiovascular, cholinergic, diuretic, and psychotherapeutic agents demonstrated a significant change in the long-term trend. We conclude that the imposition of a copayment for prescription services exerted a differential effect among therapeutic categories.
mesh_terms: D003669:Deductibles and Coinsurance; D011307:Drug Prescriptions / Q000191:economics; D004363:Drug Utilization; D005102:Health Expenditures; D006801:Humans; D008484:Medicaid / Q000191:economics*; D013022:South Carolina