The U.S. Supreme Court ruled Wednesday that patients harmed by medication can sue the pharmaceutical companies for not listing known dangers on the products warning labels approved by federal regulators.

The ruling came in a 6 to 3 vote against the drug maker Wyeth and in favor of Diana Levine, a professional guitarist and piano player who lost her right arm to gangrene after Wyeth's anti-nausea drug, Phenergan injection.

The court upheld damages of $6.7 million to Levine and ruled that U.S. Food and Drug Administration labeling approvals do not pre-empt state laws and shield companies from damages as part of liability claims.

The ruling came as a major defeat for the pharmaceutical industry that in Levine’s case used the U.S. Food and Drug Administration's approval of the drug's label in 1955, which told doctors to use extreme caution in injecting the drug but did not prohibit injections to bar all claims of negligence under state laws.

Justice John Paul Stevens said, "Congress did not intend FDA oversight to be the exclusive means of ensuring drug safety and effectiveness." He said that the federal agency "has limited resources to monitor the 11,000 drugs on the market," and added that despite FDA oversight "the manufacturer bears responsibility for the content of its label."

Levine, 63, had to have a part of her arm amputated after she was improperly injected with Phenergan as part of treatment for a migraine in 2000 and a Vermont jury awarded $7 million in legal damages. The Vermont Supreme Court upheld the verdict, prompting the company's appeal to the nation's high court.

Levine's attorneys argued Wyeth should have given stronger warnings about the dangers of administering the drug in the way she received it. While Wyeth said its labeling on Phenergan provided clear instructions and warnings and said it believed federal law prohibited it from revising the information.

"The medical and scientific experts at FDA are in the best position to weigh the risks and benefits of a medicine" and how they should be described on the product label, said Bert Rein, an attorney for Wyeth.

"It feels like a tremendous weight has been lifted off of me," Levine said in a conference call with reporters. "I feel like I did something worthwhile, which is one good thing that came out of a tragedy."

Disagreeing with the decision, Chief Justice John Roberts and justices Antonin Scalia and Samuel Alito said, "This case illustrates that tragic facts made bad law. Juries are ill-equipped to perform the FDA's cost-benefit-balancing functions."

Pfizer Inc. of New York said, "Pfizer believes that, due to its medical and scientific expertise, the U.S. Food and Drug Administration is the best authority to weigh the benefits and risks of prescription medicines and to ensure that those benefits and risks are being appropriately communicated in product labels." In an announcement in January, Pfizer had agreed to purchase Wyeth.

Stevens in the 26-page opinion said under federal law and FDA regulations, the manufacturer bears responsibility for the content of its label at all times. He said Levine presented evidence of at least 20 incidents before her injury in which a Phenergan injection resulted in gangrene and an amputation and Wyeth could have analyzed the accumulating data and added a stronger warning.

"The question we must decide is whether the FDA's approvals provide Wyeth with a complete defense to Levine's tort claims. We conclude that they do not," Justice John Paul Stevens concluded in the court's majority opinion.

Ken Johnson, spokesman for the Pharmaceutical Research and Manufacturers of America, the drug industry's main lobbying group warned the ruling could prove harmful. "Patients could ultimately suffer if the Supreme Court's decision forces healthcare providers and patients to second-guess FDA-approved labeling," said Johnson.