In a stinging rebuke that will cause financial pain, the U.S. Food and Drug Administration late Friday rejected Malvern-based Endo Health Solutions' request that the agency deny approval to generic versions of its opioid painkiller Opana ER.

Last year, Endo took the unusual step of asking the agency in a citizens petition to withdraw approval of its own drug on safety grounds. Overdose deaths from opioid painkillers now exceed those by cocaine or heroin. Besides swallowing too many pills, abusers crush, liquefy, inject and smoke the drug to get high.

Endo sought approval of a new form of the drug that Endo said was tamper resistant and wanted generics blocked from entering the market. But the FDA dismissed Endo's suggestion that its request was made on safety grounds, viewing it as a way to deter generic competitors.

Endo issued a statement Friday evening that said it could cost the company $120 million in revenue in 2013 and it was "actively pursuing cost-reduction actions that will reduce the earnings effect of FDA's decision."

It was unclear Friday evening if the cost reductions include layoffs.