A spokesman for the prescription drug industry yesterday defended the industry's common practice of selling high-priced brand-name drugs rather than lower-cost generic drugs of similar quality.

C. Joseph Stetler, president of the Pharmaceutical Manufacturers Association, told a Senate subcommittee investigating competitive practices in the drug industry that "we do not claim that all drug products marketed by brand name are high quality or that all products marketed generically are low quality."

But Stetler said, that in general the consumer is better of relying on the brand-name products of established companies than on generic drugs.

Stetler, whose testimony concluded three days of hearings by the monopoly subcommittee ofthe Senate Select Committee on Small Business, was speaking to the issue of whether doctors and pharmacists should be compelled by law to substitute lower-priced generic drugs for brand names.

Subcommittee chairman Gaylord Nelson (D-Wis.) noted that the last five Food and Drug Administration commissioners have said there is no significant medical difference between these kinds of drugs. But earlier witnesses testified that the price difference often amounts to as much as 300 to 700 per cent, and that drug companies spend four times more promoting drugs than researching and developing new ones.

Stetler took issue with a 2,000-page document, compiled by the New York state Assembly and approved by the FDA, which lists "safe, effective and medically equal" drugs. That list is being circulated in other states as a guide to what drugs can be interchanged. Stetler said, however, that FDA experts did not examine the list, and that the agency is too understaffed to inspect generic drug manufacturers to determine if their products are safe or equal to brand names.

"Forced generic prescribing might work," Stetler said, "if the FDA were perfect, if the drug industry were uniformly policed and if everyone in it were competent, and if every firm used only the latest technology and had the financial strength to compensate for product failures. But, since none of that is true today or around the corner, mandatory generic prescribing would be a serious mistake."