The US Food and Drug Administration (FDA) has been urged to revise its rules to allow generic drugmakers to update their product labeling to warn patients about risks associated with their drugs.

Currently, FDA regulations prevent generic drugmakers from updating their product labeling, even if they become aware of a potential risk not stated in the labeling, because they are required to match it to that of the original brand-name product. In contrast, branded drug manufacturers are able to update warnings and precautions on product labelling before getting FDA approval.

Advocacy group Public Citizen has filed a petition with the FDA requesting a change to the current rules, which it says are illogical.

Sales of generic drugs have skyrocketed over the past 25 years, says Public Citizen; last year, 90% of all US prescriptions for drugs with generic versions were filled with a generic rather than a brand-name drug. 

"In light of this shift, generic companies have access to a great deal of information about product safety and effectiveness and should have the same ability as brand-name companies to revise labeling to give physicians and patients the best available information about the safety of their products," the group tells the FDA.

The "illogical disparity" between labeling regulations for generic and brand-name companies was highlighted in a US Supreme Court decision this June. Ruling in the case of Pliva vs Mensing, the Court had relied on FDA regulations as the basis for its holding that patients harmed by inadequate warnings on a generic drug cannot sue the manufacturer for damages under state liability laws, although patients who take the brand-name version of the drug can do so.

The Justices commented on the "conflict" created by the current regulations, with Justice Clarence Thomas pointing out that if the generic drugmakers had independently changed their labels to satisfy their state-law duty, "they would have violated federal law," while Justice Sonia Sotomayor, dissenting from the Court decision, declared that it would lead to "so many absurd consequences that I cannot fathom that Congress would have intended to pre-empt state law in these cases."

Public Citizen filed an amicus (friend of the court) brief in this case, arguing that it is vital for all drugmakers, including generics manufacturers, to have incentives to respond to new safety information because potential hazards often do not become apparent until years after a drug has been on the market.

"Drug safety would benefit if generic manufacturers - who already have access to real-world information about adverse events - could use FDA procedures currently in place for brand-name manufacturers to revise labeling to warn of risks," said Dr Sidney Wolfe, director of Public Citizen's Health Research Group.

"The action we are requesting would bring FDA regulation in line with the realities of the pharmaceutical market and help to ensure that drug labeling provides adequate warnings to patients based on information that comes to light after the drug is approved for marketing," added Allison Zieve, director of Public Citizen's Litigation Group.