In a major policy move, the Food and Drug Administration said Tuesday that it would not approve generic versions of the powerful narcotic OxyContin, the painkiller that symbolized a decade-long epidemic of prescription drug abuse.

The move represents a victory for OxyContin’s manufacturer, Purdue Pharma, which in 2010 introduced a formulation of the drug that was less prone to tampering.

The original version of OxyContin, which was approved in late 1995, could be easily crushed, a step that released its entire narcotic payload at once rather than over time as intended. The new version turns into a jellylike mass when crushed.

Some state attorneys general and pain treatment experts had also urged the F.D.A. to block the release of generic versions of OxyContin, arguing that failing to do so would feed street demand for strong narcotics. But the decision is also likely to result in higher prices for OxyContin, a time-release form of a narcotic called oxycodone, because it will not face generic competition.