Diana Levine went to the hospital eight years ago for the same reason she had gone many times before, a migraine headache.

The treatment was the same, too - Demerol for pain and Phenergan, a Wyeth drug, for nausea.

Over the next few weeks, her lower arm turned purple and then black as gangrene set in. Doctors amputated the diseased portion of her arm in two surgeries. Levine, a musician who plays piano, guitar and electric bass and runs a children's record label, was devastated.

"My whole professional identity is gone," she said during a phone interview from her Vermont home.

"I loved playing bass. I loved being the role model of the singing female bass player, and most of all, songwriting was how I processed my life."

When she realized that Wyeth knew about the risk, she sued, in what has become a widely watched battle that goes to the U.S. Supreme Court tomorrow.

When the court rules in

Wyeth v. Levine

, sometime in the next few months, it will decide under what circumstances a consumer can sue a drug company for damages. The justices could eliminate certain pharmaceutical lawsuits altogether.

Levine won a $6.7 million judgment in Vermont state courts. Wyeth appealed, arguing that the U.S. Food and Drug Administration had final say over the risks that Wyeth put on Phenergan's label - including gangrene.

Wyeth is based in Madison, N.J., and employs thousands of people at its pharmaceutical headquarters in Collegeville. The company and its backers, including current FDA leadership, the Bush administration and the U.S. Chamber of Commerce, contend that the FDA is most able to assess the risks of drugs, especially compared with juries, which may be overly sympathetic to an injured patient.

They base their case on a legal principle known as


that says that federal law overrides - preempts - state law. Wyeth argues that it could not comply with both the FDA, which had approved the Phenergan label, and the jury verdict, which said the warning should have been stronger.

"Wyeth is placed between a rock and hard place here," the company's lawyer, Bert Rein, said.

Levine and her supporters, including two former heads of the FDA, several members of Congress, plaintiffs' lawyers, and the editors of the Journal of the American Medical Association and the New England Journal of Medicine, disagree. They say juries serve as an important check on the drug-approval system.

In the case of Merck's painkiller, Vioxx, for example, plaintiff's lawyers turned up evidence indicating that the company withheld data from the FDA about patients who died while taking Vioxx. Merck has consistently denied these allegations but pulled the drug from the market based on safety concerns.

Levine's supporters say the FDA, by its own admission, is underfunded and bases its decisions on data submitted by drug companies. They say the process of approving safety warnings is more like a negotiation between drug makers and the FDA than a top-down government order. And they argue that a pro-Wyeth ruling could severely limit consumers' ability to sue any company as preemption becomes a ruling principle.

Until at least 2002, the FDA had supported claims like Levine's, known as failure-to-warn cases, former FDA commissioners Donald Kennedy and David Kessler said.

"Litigation of that sort complements, not undercuts, FDA's job of protecting consumers from dangerous drugs," Kennedy and Kessler said in briefs supporting Levine. "Risks that are rare, have long latency periods, result from drug interactions, or have adverse impacts on subpopulations often go undetected in clinical testing."

But Daniel Troy, who headed the FDA's Office of Chief Counsel and included language favoring preemption when he oversaw the rewriting of the agency's rules in 2006, disagrees.

"When I was at the FDA, and still today, I believe patients are best-served when labeling decisions are made by scientific experts at the FDA, rather than jury by jury across the country," Troy said. He is now a lawyer for GlaxoSmithKline P.L.C.

This week, congressional investigators released internal FDA documents in which career officials said Troy's argument was based on a "false assumption that the FDA-approved labeling is fully accurate and up-to-date in a real time basis."

The Levine case is complicated. In some other cases, such as Vioxx, the risks were not well-known. But with Phenergan, the gangrene risk was known for years and is included on the drug's label.

Phenergan can be administered in three ways, and two of them - intravenous drip and muscular injection - carry minimal gangrene risk. A third quick-relief method known as "IV push" can result in gangrene if medical personnel accidentally hit an artery.

A physician's assistant administered Phenergan to Levine via IV push because she had already received a combination of Demerol and Phenergan via intramuscular injection that had not relieved her pain. Nobody mentioned the risk to her.

"When I found out [later] that the drug company knew all about this and that this could have been avoided, it was an extra layer of dismay for me - not only did I lose my hand, but I didn't have to," she said.

"This is not a cancer cure here," she said. "This is a nausea fix, and there are perfectly safe methods to deliver it."

One point of contention is whether FDA rules allow drug companies to give stronger warnings than the FDA requires.

Wyeth says it could not have changed the label without FDA approval. But Georgetown University Law professor David Vladeck said FDA rules include a big exception "when health hazards emerge. [Companies are] always allowed to change label to strengthen the warning."

The FDA argues that its regulations are "both a floor and a ceiling for labeling."

The existence of the gangrene warning on the current label may make the Supreme Court sympathetic to Wyeth, said Fordham University law professor Benjamin Zipursky.

"This is a very strategically clever case for the pharmaceutical industry to have selected," Zipursky said. "My concern is that the court will be unduly tempted to rule for Wyeth simply because it looks like Wyeth should have won this case. But in doing so, the court would do huge collateral damage to the entire area of pharmaceutical liability."

Sol Weiss, a lawyer with Anapol Schwartz who has litigated cases against pharmaceutical companies, said "if the Supreme Court comes down in a heavy-handed way, you're really giving a get-out-of jail free card to the drug industry."

Rein, however, says he is arguing only that the FDA should have the last word. "I think a lot of the publicity really takes the case well beyond its boundaries," Rein said.

Diana Levine wants a ban on the injection method used on her, so no one else is injured.

Slowly, with the help of friends, family and a therapist, she has regained parts of her old life. A special prosthesis helps her play guitar, though not as easily as she used to. Last year, for the first time, she wrote a song, "Pink Angora," on the piano with one hand.

"The industry doesn't want these pesky lawsuits, which to me are what give them incentive to help keep drugs safe," she said. "I try to break it down into questions that people can understand. What if this happened to your daughter? What if you didn't know this wasn't safe, and you went in? Would you be upset?"

What's in a label?

The legal notion of preemption, to be argued tomorrow in the U.S. Supreme Court, has its roots in the Supremacy Clause of the Constitution, which says that federal laws shall be the "supreme law of the land."

Under preemption, limits on lawsuits have been ordered or proposed on many regulated products and services, including school-bus passenger seating, to dietary sweeteners, to the design of car roofs to withstand rollovers. A few examples:

New Consumer Products Safety Commission rules require mattresses that burn more slowly but also prevent suits if a consumer is injured in a fire.

The National Highway Traffic Safety Administration issued a rule on seat-belt placement in vehicles that preempted state tort claims suits.

New Food and Drug Adminstration rules give that agency ultimate responsibility, not just input and approval, over the wording of drug labels. Companies that comply get protection.

Read documents in Diana Levine's suit against Wyeth at