Members of Congress are expressing frustration with the investigative arm of the U.S. Food and Drug Administration (FDA), with some saying the agency has been too focused on cracking down on misuse of the prescription painkiller Oxycontin, the Wall Street Journal reported June 11.

Both Republican and Democratic lawmakers have criticized the FDA's Office of Criminal Investigations (OCI), which has seen its budget double to $42.8 million since 2000. Rep. Joe Barton (R-Texas), ranking GOP member of the House Energy and Commerce Committee, has demanded to know why the FDA's arrest and conviction rate fell 20 percent between 2000 and 2006, for example, while other lawmakers have asked the Government Accountability Office to investigate whether FDA officials pressured the OCI to drop certain cases.

The OCI has traditionally operated autonomously, but Congress has limited its independence in recent years.

Barton said that OCI may be too involved in investigations into Oxycontin or precursor ingredients for methamphetamine -- areas where FDA's responsibilities may overlap with those of the Drug Enforcement Administration.