One of the Veterans Administration's largest drug suppliers paid air fare, a hotel bill and expenses for the chief of staff of D.C.'s VA Hospital to attend a medical conference in Italy this month. The Venice conference featured a blood pressure drug the firm is trying to introduce in the United States.

Dr. Robert Lindeman, staff director of the hospital, said the drug firm of Merck, Sharpe & Dohme paid his way to the Sept. 12-14 conference. The trip was approved by an "ethics counselor" at the VA, Lindeman said, despite the fact the agency sent its drug suppliers a letter shortly before the trip warning that suppliers could jeopardize their VA contracts by paying expenses or honorariums to VA personnel.

The letter was issued after a VA inspector general's probe of 75 to 100 agency employes who accepted cash, honorariums and consulting fees from major drug companies. The inspector general's office said the practices could cause conflicts of interest if VA employes made purchasing decisions based on the gratuities they received.

Lindeman said he learned of the warning letter two days before he was to depart.

"I was in touch with the general counsel's office and was told I should not handle any money directly," said Lindeman. "They bypassed me. They paid the air fare directly . . . . They the VA didn't want me to spend my money and turn around and collect a check."

Audley Hendricks, Lindeman's ethics counselor and a deputy general counsel in the VA's central office, said the drug company could pay for the trip because "we've construed that statute to allow gifts to the agency . . . . The law says the employe cannot accept cash. It's a technicality."

Hendricks said he did not approve the trip, "but I told him how to do the trip to be legal."

The trip did not enrich the doctor personally, but aided the entire agency, he said. "The agency was in the body of that doctor," Hendricks said.

Lindeman, who said he was asked to give a paper at the conference last April by the international drug company, said his wife accompanied him and they took a week's vacation in Europe after the conference. "Her air fare was not included in the arrangement," he said.

The conference involved angiotensin, a hormone released by the kidney that controls blood pressure. Lindeman, a kidney specialist, said about 50 scientists from 13 countries attended and that his paper and others will be reprinted in "Kidney International," a medical publication.

Roy Walker, a spokesman for the U.S. headquarters of Merck, Sharpe & Dohme, in West Point, Pa., said the firm plans to begin selling Vasotec, an angiotensin converting enzyme inhibitor, in the United States. The drug, which controls blood pressure, already is sold in several European countries.

Walker said the firm "agreed to reimburse the VA for Dr. Lindeman's expenses. The authorities at the VA agreed it should be a payment to the agency."

Neither the drug company nor the VA could detail yesterday the dollar amount of drugs the firm sells to the Veterans Administration each year, but several VA doctors said the amount is "substantial."

In the Fortune Magazine list of the 500 largest industrial corporations in 1984, Merck, the parent company of Merck, Sharpe & Dohme, ranked 110th in sales ($3.6 billion) and 11th among all 500 corporations for net income as a percentage of sales. Among pharmaceutical firms, Fortune ranked Merck seventh among 19 companies.

Lindeman said attending the European seminar at the drug firm's expense will not affect his attitude toward the company or its products. "I certainly don't expect to do anything to favor Merck, Sharpe & Dohme," he said. "This is the kind of practice that's gone on for years in the VA and in medical schools."

Attorney Hendricks added, "The drug companies fund an incredible amount of research . . . . It's fairly sensible to use what resources are available." The trip "is something of value that we could have paid with adequate travel funds."

The agency relies on the professionals invited to seminars to determine if they're worth attending, Hendricks said. If so, outside firms can pay for the VA employes to attend as long as the employes are on official business, he said.

"The drug companies schedule them some place to make them attractive," he noted.

Asked whether drug companies could be trying to influence VA officials by offering European trips, Hendricks said, "We might want them to. If they've got a wonderful drug, we want to know about it."

He added that Lindeman "has influence" in purchasing, but " . . . there's a procurement mechanism" of purchasing committees that dilutes any individual's influence.

An investigator in the inspector general's office said the investigation into payments by drug companies is continuing.