WASHINGTON (Reuters) - The House Wednesday passed a bill that would effectively overturn Oregon's physician-assisted suicide law while promoting more aggressive pain relief for people near the end of life.

The vote on the ``Pain Relief Promotion Act'' was 271-156, with a few dozen crossing party lines in either direction. The Senate is likely to take up companion legislation before Congress adjourns next month.

Sponsors, led by Illinois Republican Henry Hyde, argued that the bill would promote better pain management while preventing doctor-assisted suicide or euthanasia.

The bill would amend the 1970 Controlled Substances Act to make clear that narcotics cannot be used to cause death, no matter what a state law says. The drugs can be prescribed for the purpose of controlling pain, even if the medication hastens death by depressing respiration.

The bill does not explicitly repeal Oregon's law, but basically renders it meaningless by preventing doctors from prescribing the drugs.

During the often emotional debate, Hyde said the Oregon law devalues human life in a way that threatens the elderly, the uninsured, the disabled and the ``unwanted.'' He said it transforms doctors into ``messengers of death.''

``They can put down their stethoscope and pick up the poison pill,'' Hyde said.

Opponents, including some 10 people who oppose assisted-suicide but disagreed with Hyde's approach, said the bill would have the opposite effect.

They said it would deter aggressive treatment of pain by making doctors fear that they could end up in jail for prescribing potent medications.

They objected to allowing Drug Enforcement Administration agents, who have no medical training, to review how a doctor prescribes pain-killers.

``There is already an undertreatment of pain in America. Don't make it worse,'' said New Jersey Democrat Steven Rothman.

Various medical groups were split on the legislation, although the American Medical Association backed Hyde.

Oregon in 1994 became the first state to enact an assisted-suicide law, after a voter referendum. It was held up in a court battle but after an appeals court ruling and a second, stronger voter referendum, it went into effect in November 1997.

The Oregon law permits physician-assisted suicide by terminally-ill people who are judged mentally competent and whose doctors give them less than six months to live.

In the first full year the Oregon law was in effect, 15 people did commit suicide. Most were cancer patients.