AmerisourceBergen said it received subpoenas from U.S. prosecutors and the Drug Enforcement Administration seeking information on how the company monitors for potential diversions of drugs with high potential for abuse.

The pharmaceutical wholesaler said in a regulatory filing that one of its units received a subpoena in May from the U.S. Attorney's Office in New Jersey in connection with a grand jury proceeding and another from the DEA.

The subpoenas requested documents concerning a program for controlling and monitoring diversion of controlled substances into channels other than for legitimate medical, scientific, and industrial purposes, the company said in the filing with the U.S. Securities and Exchange Commission. Documents concerning specific customers' purchases of controlled substances were also sought, the company said.

Federal and state authorities have been working to stem the widespread abuse of prescription painkillers and other controlled substances that many experts believe has reached epidemic proportions in the United States, including investigations of companies that distribute such medicines.

Amerisource rival Cardinal Health earlier this year agreed to suspend shipments of controlled substances from a Florida distribution center for two years under a settlement with federal prosecutors stemming from the crackdown on abuse of prescription pain drugs, such as Vicodin and Oxycodone.

Amerisource declined to name the specific customers on which federal investigators were seeking information, saying it could not comment on the ongoing investigation. In the filing it said its ABDC unit was in the process of responding to the subpoenas and cooperating fully with the U.S. Attorney's office and the DEA.

"Obviously we take diversion very seriously and will continue to cooperate with the authorities," AmerisourceBergen spokeswoman Barbara Brungess said.

"Our facilities are all operating normally and we are shipping to customers as we normally do," she added.