WHAT ARE THE ETHICS when an American-based multinational drug company sells products abraod by overstating the benefits and under-stating the dangers? The answer has its variables, but the practice is longstanding. HAppily, the pharmaceutical Manufacturers Association in Washington has joined those who taken a stand such double-dealing.

Hearing last year before the Senate Small Business Monopoly Subcommittee revealed that promotional claims for drugs sold by American, Swiss and other global frims in Latin American markets were often designed to exploit physicians and consumers in one country or another by routinely withholding information on dangerous side effects. After the hearings, C. Joseph Stetler, president of the PMA, pressed for reforms. Recently the International Federation of Pharmaceutical Manufacturers endorsed a policy calling for procedures that would end the practice.

Mr. Stetler's initiative has had some impact. A California drug specialist, Dr. Milton Silverman, probably the most effective critic of this abuse, has compared the statements of 15 global drug firms: what they were telling Latin American doctors in 1973 and what they were saying in 1976, The conversions are anything but born-again miracles, but a definite toning down is present is some cases. Parke-Davis, for example, was telling Latin American doctors in 1973 that its Chloromycetin was suitable for such disoders as tonsillitis or ear and eye infections. To American doctors, a different labeling message was given: Use for only a few serious or life-threatening illnesses, to avoid the possibility of causing a fatal blood disease in some users. In 1976, Dr. Silverman reports, Parke-Davis was speaking in one tongue.

How many people have been vitimized by past duplicity can't be known. Grave injuries have surely been suffered by may of those who trusted the labels. For now, it is encouraging that the protests of Dr. Silverman and others have had the the ulitmate result of stimulating voluntary restraints by some of the American drug companines. That is far from the total solution, if only because the Latin American market includes European and local firms as well. Pressure is likely to be kept up, however, in those situations in which the old double-dealing persists.