There is a hot issue in the Darvocet/Darvon/propoxyphene lawsuits as whether suits involving Darvon are preempted by federal law because it is a generic drug. The MDL judge overseeing these cases let Darvon off the mat, finding that all claims against it against generic drug makers of the generic equivalent of Darvon are either preempted under PLIVA v. Mensing (and that the claims that were not preempted were defective).
Plaintiff have now appealed this decision to the Sixth Circuit U.S. Court of Appeals.