A Sun Pharmaceutical unit was named in a suit over product-labeling liability. Agence France-Presse/Getty Images

A new case that could reach the Supreme Court will test generic-drug makers' liability over product labeling.

At issue is how quickly those companies need to match changes in labeling that are made by equivalent brand-name medicines. The case represents yet another contentious effort to interpret federal and state laws governing liability for medicines, a topic that has embroiled the pharmaceutical industry, regulators and the courts for the last several years.

The Supreme Court held three years ago that generic makers can't be held accountable for failing to warn about risks that haven't been identified by the branded manufacturer. The new case, which the Supreme Court has been asked to review, would test generic manufacturers' responsibility when the risks are known.

The case involves Olga Pikerie, a California woman who was prescribed a generic version of Fosamax, a medicine used to treat osteoporosis. The lawsuit claims that she suffered harm because the risk information for the medicine was insufficient.

The labeling on the brand-name drug, which is sold by Merck & Co., was updated in 2010 and again in 2011 to warn about risk of femur fractures. Comparable changes to the generic labeling were made six weeks after each update, according to court documents.

Ms. Pikerie suffered a fracture in April 2011. But she hadn't been warned of those risks, according to her attorney, because her physician was unaware of any side-effect warnings that may have applied to the generic versions. Her lawyer, Mark Crawford, maintains the generic-drug makers could have quickly alerted physicians with Dear Doctor letters—a standard notice about important product updates—but he says that this wasn't done between the time Merck updated its labeling and the generic drug makers did the same.

"Once the brand changed the label, the generic was free to send any communication to the doctor about any information in the approved label," says Mr. Crawford.

In court documents the generic-drug makers— Teva Pharmaceutical and Caraco Pharmaceutical, a unit of Sun Pharmaceutical —cited an FDA regulation in arguing that they are unable to update labeling with new safety information quickly or send warnings to physicians unless the brand-name drug makers do so first.

The Supreme Court ruled in 2011 that generic drug makers aren't permitted to independently add new side-effect information to product labeling and, therefore, shouldn't be held accountable for a failure to warn against any risks. Essentially, the court ruled that generic-drug makers can act only after a brand-name drug maker makes such a change.

In this case, the brand-name drug maker had already made the change and Mr. Crawford argues the generic-drug makers that sold copycat versions of Fosamax were, in fact, able to send a communication to her doctor about the risk information. A California appeals court last year ruled against Teva Pharmaceuticals and Caraco Pharmaceuticals, saying Ms. Pikerie's claims were permitted under state law.

The generic-drug makers argue the California appeals court was mistaken, because federal law pre-empts, or supersedes, state law governing the failure of a company to warn about the risk of its product.

Sun Pharmaceutical declined to comment and Teva didn't respond to requests for comment.

"I think the issue presented in this case is whether we want juries to second guess the authority and discretion of the FDA, which is charged with drug safety," says Jay Lefkowitz, who represents the drug makers and argued the 2011 case before the Supreme Court. "Do we really want juries to decide the question of when generic drug makers should update their labeling or do we rely on the FDA?"

Meanwhile, the generic-drug companies make a more sweeping argument: that any attempt to enforce a violation of the Food, Drug and Cosmetic Act—such as failing to update product labeling—can be brought only by the federal government, not another party.

"A decision in this case against the generics could open the door to many, many lawsuits," says Kurt Karst, who runs the FDA Law blog and an attorney at Hyman Phelps & McNamara, a law firm that specializes in FDA regulatory matters.

Of course, the issue may become moot if the FDA follows through with plans to issue a new rule that would permit generic-drug makers to update labeling independently in response to new risk information.

Earlier this summer, the Supreme Court asked the Obama administration its view on the degree to which the ruling hinders its ability to regulate pharmaceuticals. The court is expected to decide whether to hear the case next fall.

Write to Ed Silverman at Ed.Silverman@wsj.com