In 2011 there was a US Supreme Court ruling that pharmaceutical companies making drugs during the life of their patent are liable for inadequate safety warnings on the label of the drug. In June of 2013 the same court ruled that generic drug producers were NOT liable for law suits related to adverse drug reactions not printed on the label so long as they are not purposefully being withheld. This federal law supercedes any state laws to the contrary.
Of course this is a blow to patient safety as generic drug makers would no longer have incentive to monitor the safety of their products.