Generic drugmakers are actively campaigning against a rule proposed by the U.S. Food and Drug Administration (FDA) that would require them to change the prescribing information on their products if they receive new safety information.

This, they contend, would open the door to liability lawsuits as well as increasing the cost of drugs and leading to confusion among consumers.

The FDA proposal, dating from November 2013, was planned to be discussed by the U.S. House of Representatives Energy and Commerce Committee's health during a hearing on Mar. 3. If it becomes law it would overturn regulations in place for three decades that prohibit generic drugmakers from updating safety data on their labels without prior approval of the drug's developer.

The FDA said the change is designed to "create parity" between branded and generic drug makers with respect to labelling changes and remove an unnecessary impediment to the prompt communication of safety data.

In 2011, after years of legal wrangling, the U.S. Supreme Court ruled that the FDA's existing prohibition on label changes meant that generic drugmakers should not be held accountable for a failure to warn against risk. As a result, consumers injured by a brand name drug could have legal recourse, but those affected by a generic effectively could not.

The current proposal would remove that protection while placing equal responsibility for monitoring drug safety on the original producer and the generic manufacturer. Supporters of the change say this is particularly important as around 2,000 generic drugs - about 45 percent of all those on the market - no longer have a branded counterpart.

Currently, generic drugs account for some 80% of all prescriptions filled in the U.S.