By a 5-4 vote, the justices gave a victory to Israel's Teva Pharmaceutical Industries Ltd, Mylan Inc's UDL Laboratories and Iceland-based Actavis Inc by overturning U.S. appeals court rulings that allowed such lawsuits. Liberal Justices Sonia Sotomayor, Ruth Bader Ginsburg, Stephen Breyer and Elena Kagan dissented.
"It was impossible for the manufacturers to comply with both their state-law duty to change the label and their federal law duty to keep the label the same," Justice Thomas wrote in a 20-page opinion.
The high court on Thursday ruled against Gladys Mensing, who had sued PLIVA Inc. and other generic drug manufacturers.
She alleges that taking metoclopramide gave her tardive dyskenesia, but none of the generic drug's manufacturers and distributors made any effort to include warnings on the label.
Generic drug makers say government regulations require them to have the same label on metoclopramide as is on its brand-name equivalent, Reglan. Reglan did not have a warning about tardive dyskinesia. The drug is often taken for heartburn.