U.S. drug regulators asked on Friday for manufacturers of prescription pain medications to provide more specifics on an industry plan to curb growing abuse of morphine, methadone, oxycodone and other opioid drugs.

The Food and Drug Administration in February had asked manufacturers including Johnson & Johnson and King Pharmaceuticals to come up with a joint plan to deal with the public health problem, particularly involving slow release and long acting versions of the drugs. This is the first time the agency has sought to develop risk evaluation and mitigation strategy for an entire class of drugs.

At a Friday meeting, industry representatives told FDA they intended to develop a phased-in approach to deal with the problem. This could include a voluntary training program for doctors to better educate them about proper use of pain killers and government certification for prescribing of controlled substances.

Currently, a physician must be certified by the U.S. Drug Enforcement Agency to prescribe this class of drugs. Congress would have to approve any requirement for physician training to receive DEA certification.

The director of the FDA's Office of New Drugs, John Jenkins, said the goal was to find a balance between reducing abuse of the drugs and maintaining access for patients who need the pain killers.

There was concern that doctors might opt out of prescribing the pain killers if the requirements are too burdensome.

FDA will hold more meetings with the industry group, doctors and the public next year.