The U.S. Supreme Court ruled that design defect claims against generic drugmakers cannot be brought under state laws because federal law preempts them, a ruling that insulates manufacturers from liability when people who use their drugs are harmed by them.

The 5-4 decision in Mutual Pharmaceutical Co. v. Bartlett overturns a $21 million verdict for Karen Bartlett, who suffered from toxic epidermal necrolysis, a skin condition that resulted from the use of sulindac, a generic version of the pain medication Clinoril. The condition caused Bartlett to suffer deterioration, burns, and open wounds over as much as 65 percent of her body. She was in a medically induced coma, underwent 12 eye surgeries, and needed to be tube fed for a year. She is permanently disfigured, suffers from multiple disabilities, and is nearly blind.

In 2005, after she had developed the condition, the U.S. Food and Drug Administration recommended changes to the label for nonsteroidal anti inflammatory drugs including Clinoril and its generic versions. Bartlett sued the maker, Mutual Pharmaceutical, alleging a design defect and a New Hampshire jury awarded her $21 million in damages. Mutual is a subsidiary of Sun Pharmaceutical Industries.

Under New Hampshire law, manufacturers must ensure their products are not “unreasonably dangerous.” But the opinion authored by Justice Samuel Alito, Jr., notes that Mutual could not change sulindac’s design or label without violating the federal law that requires a generic drug to have the same active ingredient, administration, dosing, strength, and label as the brand name drug.

Bartlett’s attorney argued that sulindac’s label carried an inadequate warning about its risk and the New Hampshire jury agreed. But Alito said that under federal law Mutual was prohibited from taking the action necessary to avoid liability under New Hampshire law and that the supremacy clause of the Constitution that places federal law above state laws. He said that the Federal Food, Drug, and Cosmetic Act pre-empts the state requirement.

“Respondent’s situation is tragic and evokes deep sympathy, but a straightforward application of pre-emption law requires that the judgment below be reversed,” wrote Alito.

In her dissenting opinion, Justice Sonia Sotomayor argued the majority failed to apply established pre-emption principles properly. “By once again expanding the scope of impossibility pre-emption, the Court turns Congress’ intent on its head and arrives at a holding that is irreconcilable with our precedents,” she writes. “As a result, the Court has left a seriously injured consumer without any remedy despite Congress’ explicit efforts to preserve state common-law liability.”

The 5-4 vote broke along ideological lines with justices Roberts, Scalia, Kennedy, and Thomas joining Alito in his opinion and justices Breyer, Kagan, Sotomayor, and Ginsburg dissenting.