Changes in related drug class utilization after market withdrawal of cisapride.

BACKGROUND: Recent Food and Drug Administration-mandated and company-initiated withdrawals of drug products from the marketplace have had an impact on utilization in related drug classes. OBJECTIVE: To investigate the impact of withdrawal of the prokinetic agent cisapride (Propulsid) on utilization of other gastrointestinal (GI) agents. STUDY DESIGN: A longitudinal, retrospective study using electronic prescription data from a state-funded geriatric prescription benefit program. PATIENTS AND METHODS: Prescription claims for 2644 patients using cisapride between January 10, 2000, and October 1, 2000, were analyzed with respect to points in time at which (1) prospective drug utilization review edits were implemented denying reimbursement of cisapride because of drug interactions, (2) the manufacturer announced its intent to cease production, and (3) the agent was withdrawn from the market. Prevalence of use, claims volume, and expenditures were compared for cisapride, proton pump inhibitors, histamine-2 receptor antagonists, and the prokinetic agent metoclopramide during these periods. RESULTS: Use of cisapride decreased precipitately even before implementation of a "medical exception only" reimbursement policy. After the change in policy, metoclopramide use increased, although this increase was not proportional to cisapride's decline. Although total GI expenditures declined within the cisapride cohort, this change had little impact on overall program GI expenditures. CONCLUSIONS: The loss of cisapride did not significantly affect program-wide costs for GI drugs. However, the withdrawal of cisapride appears to have resulted in increased use of metoclopramide, a medication with a more serious adverse effect profile than cisapride. Further study is needed to evaluate the long-term clinical impact of such therapy changes.