The Drug Enforcement Administration (DEA) announced this week that U.S. pharmaceutical companies have voluntarily agreed to restrict access to larger-dose methadone tablets beginning on Jan. 1, 2008.

The 40-mg methadone hydrochloride tablets will only be distributed to hospitals and authorized opiate addiction and detoxification facilities, the DEA announced. The move was intended to curb the rising number of methadone overdoses and illegal diversion of the drug.

"The 5 mg and 10 mg formulations indicated for the treatment of pain will continue to be available to all authorized registrants, including retail pharmacies," according to the agency. "The 40 mg strength is not FDA approved for use in the management of pain. Thus, the distribution and availability of the 40 mg formulation will be limited to registrants in only those settings using the 40 mg formulation for the appropriate indication" -- namely methadone maintenance for opiate addicts.