Heroin is not a better pain reliever than morphine, a medical team at New York's Memorial-Sloan Kettering Cancer Center reports in the lead article of the New England Journal of Medicine.

Given this, "the Legalization of heroin for medical use does not seem socially responsible," says an editorial by Dr. Louis Lasagna of the University of Rochester in the issue.

Many cancer patients and others have been arguing since the 1960s that doctors often do not give terminally ill patients enough pain relief, and that heroin would be a potent way to do so.

Many doctors and laymen still think that is true, Reps. Henry A. Waxman (D-Calif.) and Edward R. Madigan (R-Ill.) are authors of bills to make heroin medically available. The bills have wide bipartisan support.

The Sloan-Kettering group tried various doses of heroin and morphine, already a hospital staple, in 166 cancer patients with pain after surgery.

Heroin, say Dr. Robert Kaiko and colleagues, proved about twice as potent as morphine and, thus, it took less heroin to do the same job.

Heroin also acted somewhat faster. But morphine's effect lasted longer, and there were no essential differences in pain relief or mood, including the euphoria that illegal heroin-users seek.

The main "side-effect" of both drugs was sleepiness which occurred in nearly half the patients who took either.

Heroin is more easily dissolved in water than morphine. This, plus its greater strength, make it superior for some patients, according to advocates.

These include Dr. Philip Schein, chief of medical oncology (cancer treatment) at Georgetown University. Georgetown Drs. William Beaver and Schein recently studied 48 terminally ill cancer patients with moderate and severe pain.

They, too, found morphine and heroin equally effective in relieving pain. None of their patients felt euphoric. But they felt heroin would be more effective for patients who need large doses of narcotics, and should be available to doctors for patients who need it.

Heroin is actually a morphine derivative. And if a superior drug is needed for some patients, another morphine derivative, Dilaudid, is even better than heroin, according to the Sloan-Kettering group. Dilaudid is readily available on a doctor's prescription.

Heroin came in widest notice in medicine after doctors at London's St. Christopher's Hospice started using it in a heroin-cocaine-alcohol "cocktail" for patients slowly expiring and suffering pain.