The Food and Drug Administration yesterday altered a long-standing regulatory policy, making it possible for U.S. troops serving in the Persian Gulf to be given experimental drugs without their consent.

The new "interim rule," established at the request of the Defense Department, is intended to provide flexibility in countering the effects of chemical and biological weapons. Published in the Federal Register yesterday, the policy went into effect immediately because of "the urgency created by current military operations in Operation Desert Shield."

The policy gives the FDA authority to permit administration of "investigational drugs and biologics" without obtaining the "informed consent" of soldiers if the commissioner of food and drug deems that such consent "is not feasible" in battlefield conditions. The federal Food, Drug and Cosmetic Act requires that persons who are to receive investigational drugs be informed of the substances' experimental nature and give their consent to the treatment.

The Defense Department requested the action on Oct. 30. For some threats of "endemic diseases" and chemical and biological weapons, the request stated, "we have determined that the best preventive or therapeutic treatment calls for the use of products now under 'investigational new drug' (IND) protocols." The Pentagon also argued that informed consent would not be practicable in some cases of "actual or threatened" military combat.

The agency would not identify either the types or number of drugs that might fall under the new rule. "But these are agents for which the evidence of safety is there," FDA spokesman Jeff Nesbitt said.

"We have nothing exotic in the works," the Pentagon's Oct. 30 request said. "These drugs have well-established uses (although in contexts somewhat different from our requirements)," and include "a very commonly used drug packaged in a special intramuscular injector," a vaccine whose questionable effectiveness has kept it from being fully licensed by the FDA, and "a drug in common use at a particular dosage level" which would be administered in lower doses "to preserve alertness of the soldiers."

Experts in chemical and biological weapons, surprised by the FDA announcement, were uncertain as to what IND compounds might be involved.

"I think our troops are fairly well protected already," said Harvard biochemist Matthew Meselson, a longtime specialist in chemical and biological warfare (CBW). "The gas masks in use protect against all known chemical and biological weapons. And very few agents attack the skin. For those that do, the {military's protective} suit is admirable and complete protection" against the CBW agents most likely to be deployed against U.S. troops, including mustard gas, anthrax, tularemia and organophospate compounds, similar to insecticides but more toxic.

But "the main casualty-producing threat will be conventional weapons, shrapnel and explosives for which there is no such protection," Meselson said. "I suppose there are thousands of {drugs} that might be useful, but their relative importance is not overwhelming."

The new FDA rule may also raise ethical and legal questions. "Obviously, consent is not possible in the heat of battle," said Sidney M. Wolfe, director of Public Citizen Health Research Group. "But if these are drugs that they already know something about, and they know the target population, then why couldn't they get consent in advance? It just sounds absurd."

Arthur Caplan, director of the Center for Biomedical Ethics at the University of Minnesota, said that "waiving informed consent may raise questions later about liability. Ordinarily, a manufacturer presumably will be liable if a drug is later found defective. Does this mean that soldiers are not just waiving their consent, but also their ability to claim harm later?"

"The war creates special and anomalous circumstances," Caplan said. "But should it be used as a rationale for the loss of normal protections that all citizens should have with respect to experimental drugs? The FDA and the military should be trying to think ahead to anticipate just this kind of problem -- which looks to me like it could have been anticipated."