Asthma Healing

By PHILIP M. BOFFEY, SPECIAL TO THE NEW YORK TIMES

Leading experts and professional groups are challenging the Food and Drug Administration's approval of the nonprescription use of an inhaler drug for asthma.

The critics acknowledged this week that the inhaler, long available by prescription, was safe and effective if used properly to gain relief from asthmatic wheezing and shortness of breath. But they believe that many people will now use it in excess of recommended dosages, possibly causing cardiac arrest or allowing respiratory failure to occur undetected until too late.

The new nonprescription inhaler has recently begun appearing on drugstore shelves, where it is available to millions of American asthmatics and others.

One expert who hopes to reverse the agency's action, Dr. Leslie Hendeles, associate professor of pharmacy at the University of Florida in Gainesville, warns, ''Patients may wind up in the hospital more frequently, they'll be sicker when they get there, and there is a possibility that we may face an epidemic of deaths among asthmatics.'' Agency Action Defended

But James P. Mann, the F.D.A. physician who helped manage the change in the drug's status, said in a telephone interview, ''I remain totally convinced that we did a good thing.'' He said the action was part of an effort to make an increasing number of safe and effective drugs available without prescription.

The dispute erupted after the agency decided that a drug known as metaproteronol sulfate, previously available only by prescription, could safely be sold to the public ''over the counter,'' without a prescription. The drug is marketed under the brand names Alupent, manufactured by Boehringer-Ingelheim Ltd., and Metaprel, manufactured by Dorsey Laboratories, a division of Sandoz Inc.

The critics are not directing their fire at other inhaler drugs that have long been available without prescription, such as the epinephrine compounds, marketed under such brand names as Primatene and Bronkaid mists, though a few experts have expressed reservations about those inhalers, too. Rather, the experts are concerned now about metaproterenol sulfate because of its greater potency and its newly acquired nonprescription status. 'Real Possibility of Abuse'

Dr. Raymond Slavin, president of the American Academy of Allergy and Immunology, complained in an interview: ''The medical and scientific community was not adequately consulted before this decision was made. There is a real possibility of abuse of this very potent medication.''

Dr. Alfred Soffer, executive director of the American College of Chest Physicians, said his organization was ''alarmed because these are powerful agents.''

Dr. Rufus Lee, president of the American College of Allergists, expressed ''considerable reservations'' about the F.D.A.'s decision. Dr. Gail Shapiro, chairman of the allergy section of the American Academy of Pediatrics, chided the agency in a letter for taking ''a step backwards.''

The decision to make metaproterenol sulfate nonprescription was announced by the agency's staff last October without consultation of any of the agency's expert advisory panels and without a formal request from the manufacturers. It was the first time that the agency had initiated such a switch to over-the-counter status on its own, without receiving an application from industry, according to F.D.A. officials. Supervision Held Necessary

In a telephone interview, Dr. Hendeles said that the drug had ''an excellent safety record'' when administered by medical prescription. But he said that, when medical supervision was absent, ''patients with asthma tend to overuse and abuse'' the inhalers.

Although patients are supposed to use the inhalers only once every three hours, he said, if their condition worsens they often increase the frequency or dose of inhalation, thus gaining temporary relief but delaying a visit to the doctor for treatment that may be needed to prevent complete respiratory failure. ''People are found dead with their inhalers in their hands,'' he warned.

Dr. Hendeles said there were''epidemics of deaths'' among asthmatics in Australia and in England and Wales in the 1960's that some experts have attributed in part to excessive use of nonprescription inhalers, including metaproterenol.

Many experts also express concern that the drug may cause heart problems in susceptible individuals. Indeed, the 1983 edition of the Physicians Desk Reference warns that excessive use is ''potentially dangerous,'' adding, ''Fatalities have been reported following excessive use'' and that ''cardiac arrest was noted in several cases.''

Dr. Mann of the F.D.A., who is himself a certified specialist in pulmonary medicine with decades of experience in treating asthmatics, said he personally believed metaproterenol sulfate was less apt to be misused than the epinephrine compounds that have long been widely available. ''I myself am quite confident that epinephrine is not as safe or effective as metaproterenol,'' he said, ''but I haven't got a data base that would stand up in front of a judge.''

Dr. Mann suggested that some critics had ''their noses out of joint'' because the agency had failed to consult key advisory panels and that others were opposed to ''the whole concept of over-thecounter marketing'' with its emphasis on self-medication by patients.