The metoclopramide black box warning for tardive dyskinesia: effect on clinical practice, adverse event reporting, and prescription drug lawsuits.

Abstract

We examined the effects of the black box warning about the risk of tardive dyskinesia (TD) with chronic use of metoclopramide on management of gastroparesis within a single clinical practice, and on reporting of adverse events. Medical records of gastroparesis patients were evaluated for physician management choices. The FDA Adverse Event Reporting System (FAERS) was analyzed for event reports, and for lawyer-initiated reports, with metoclopramide from 2004 to 2010. Google Scholar was searched for court opinions against metoclopramide manufacturers. Before the black box warning, 69.8% of patients received metoclopramide for gastroparesis, compared with 23.7% after the warning. Gastroenterologists prescribed domperidone more often after than before the warning. Metoclopramide prescriptions decreased after 2008. Adverse event reporting increased after the warning. Only 3.6% of all FAERS reports but 70% of TD reports were filed by lawyers, suggesting a distortion in signal. Forty-seven legal opinions were identified, 33 from 2009-2010. The black box warning for metoclopramide has decreased its usage and increased its rate of adverse event reporting. Lawyer-initiated reports of TD hinder pharmacovigilance.