The US Supreme Court has ruled that generic drugmakers cannot be sued by patients who suffer adverse reactions caused by their products, because the companies did not develop the drugs nor seek their initial approval.

Therefore, the generics makers cannot be sued for any defects in the original drug’s design, said the Court, ruling in the case of Karen Bartlett, who suffered serious adverse reactions after taking a generic version of Merck & Co's non steroidal anti-inflammatory drug (NSAID) Clinoril (sulindac) made by Mutual Pharmaceutical Co, a subsidiary of Sun Pharmaceutical Industries of India.

In 2010, Ms Bartlett was awarded $21 million by a federal jury in New Hampshire for developing Stevens-Johnson syndrome as a result of taking Mutual's sulindac, but the Supreme Court decision has now overturned that ruling.

Commenting, the Generic Pharmaceutical Association (GPhA) said the Supreme Court ruling upholds a key principle - that decisions about the safety and efficacy of prescription drugs should rest with the scientific experts at the Food and Drug Administration (FDA). The industry group also points out that sulindac has been on the market for more than 30 years, and was "was prescribed and dispensed more than 300 million times between 2007-12 with a typical safety profile."

However, in a dissenting opinion to the 5-4 Court decision, Justice Sonia Sotomayor comments that "the Court has left a seriously injured customer without any remedy, despite Congress's explicit efforts to preserve state common-law liability," while other critics argue that generic drugs are not necessarily bioequivalent with the original branded versions.

The current regulations, which do not permit generic drugmakers to update product labelling to reflect newly-discovered information abut safety risks unless they are mimicking a change already made by the branded maker or ordered by the FDA to revise the labelling, are putting patients at risk, warns advocacy group Public Citizen.

While the generic maker is required to match its labelling to that of the branded version, brand-name drugmakers are permitted to update warnings and precautions on product labelling before getting FDA approval. Yet many potential hazards are not discovered until years after drugs have been on the market, says Public Citizen, which has published a new report showing that at least 53 drugs approved by the FDA more than 10 years ago have required new black-box warnings during the past five years.

In addition, 434 generic drugs are currently available in the US for which no branded original products remain on the market, it says.

Of the 53 drugs for which the FDA has required a new black-box warning, 11 are currently marketed only as generics, while 38 are still marketed in both branded and generic versions, one is sold only as a brand-name drug and three are no longer on the market, the report shows.

In August 2011, Public Citizen submitted a citizen petition to the FDA, requesting that it amend its regulations to allow generics makers to use the same procedures for updated labelling that are currently available to brand-name firms. Pointing out that 80% of prescriptions in the US are filled with generics, it says that such an amendment would help to ensure that drug labelling provides adequate warnings to patients based on information that comes to light after the drug is approved for marketing.

And pointing to the Supreme Court's 2011 decision in the case of Pliva vs Mensing - which was similar to its ruling in Mutual Pharmaceutical Co vs Bartlett - Public Citizen says that amending the regulations in this way "would correct the illogical disparity between the rights of patients injured by generic drugs and the rights of those injured by brand-name drugs."

Public Citizen says that the FDA “has not responded substantively” to its citizen petition.