After Purdue and Endo Pharmaceuticals ($ENDP) developed new, tamper-resistant versions of their often-abused narcotic painkillers, they're now trying to stop generic drugmakers from rolling out copycats of the older drugs now coming off of patent protection. The drug companies say it's a safety issue. The generic competition, though, says it's about economics. Patients shouldn't be denied cheaper meds, they say, which can be very safe if used properly. With a big chunk of a $9 billion drug market up for grabs, this is one argument that is likely to continue for some time. Story (sub. req.)