Context Cisapride, a gastrointestinal tract promotility agent, can cause life-threatening
cardiac arrhythmias in patients susceptible either because of concurrent use
of medications that interfere with cisapride metabolism or prolong the QT
interval or because of the presence of other diseases that predispose to such
arrhythmias. In June 1998, the US Food and Drug Administration (FDA) determined
that use of cisapride was contraindicated in such patients and informed practitioners
through additions to the boxed warning in the label and a "Dear Health Care
Professional" letter sent by the drug's manufacturer.
Objective To evaluate the impact of the FDA's 1998 regulatory action regarding
contraindicated use of cisapride.
Design and Setting Analysis of data for the 1-year periods before (July 1997-June 1998)
and after (July 1998-June 1999) the regulatory action from the population-based,
pharmacoepidemiology research databases of 2 managed care organizations (sites
A and B) and a state Medicaid program (site C).
Participants Patients with at least 180 days of prior enrollment in 1 of the 3 sites
who were prescribed cisapride at least once in the period before (n = 24 840)
or after (n = 22 459) regulatory action. Patients could be included in
Main Outcome Measures Proportion of cisapride users in each period for whom cisapride use
was contraindicated by the product label, based on computerized patient medical
Results In the year prior to regulatory action, cisapride use was contraindicated
for 26%, 30%, and 60% of users in study sites A, B, and C, respectively. In
the year after regulatory action, use was contraindicated for 24%, 28%, and
58% of users, a reduction in contraindicated use of approximately 2 per 100
cisapride users at each site. When the analysis was restricted to new users
of cisapride after regulatory action, only minor reductions in contraindicated
use were found.
Conclusion The FDA's 1998 regulatory action regarding cisapride use had no material
effect on contraindicated cisapride use. More effective ways to communicate
new information about drug safety are needed.