Federal officials said yesterday that they are weighing a recommendation that the government consider prosecuting officials of Eli Lilly and Co. for allegedly failing to report "important adverse findings" linked to four marketed experimental medicines.

One of the medicines is Oraflex, an arthritis drug associated with 45 deaths among 500,000 users in the United Kingdom. On Monday, the Public Citizen Health Research Group filed suit to force the Health and Human Services Department to act on its petition to halt sales of Oraflex as "an imminent hazard to the public health."

Last September, Dr. Michael J. Hensley, a former Food and Drug Administration medical officer, made the recommendation for a possible prosecution after a two-year investigation. A similar recommendation was made by FDA inspectors in Indianapolis, Lilly's home base. Hensley and the inspectors joined in pursuing allegations made by James T. Campbell, a former Lilly employe.

The Hensley memo spoke of internal records at Lilly that "are sparse or non-existent as a matter of policy," of reports to the FDA that "were untrue or incomplete," and of Oraflex data that "appears to have been deliberately withheld, thus biasing the marketing application in favor of approval."

Rep. L. H. Fountain (D-N.C.), chairman of a House Government Operations subcommittee, disclosed the memo during the six-hour opening session of a two-day hearing on whether purported long-time FDA laxity and Reagan administration drug "deregulation" proposals imperil public health. Vice President Bush, chairman of the President's Task Force on Regulatory Relief, is a former director of Lilly, a leading pharmaceutical manufacturer.

Fountain chided the agency for its delay in acting on Hensley's recommendation, and pointed out that the FDA had referred to the Justice Department a case involving nonreporting of alarming reactions in users of Selacryn, a drug for high blood pressure that was sold by Smithkline Beckman Corp.

But Commissioner Arthur Hull Hayes Jr. and other FDA officials said they needed time to cope with the complex ramifications of the Hensley memo. They said they could not comment on the Selacryn case.

Lilly Vice President Edgar G. Davis, in a statement to reporters, said that the company "takes vigorous exception to any implication that it has withheld data, maintained inadequate records or failed to comply with the scientific reporting requirements of the FDA."

In addition to Oraflex, which the FDA cleared for sale last April 19, the Hensley memo cited Aprindine and Drobuline, which are experimental drugs considered for persons with irregular heart beat, and Monensin, a marketed cattle-feed supplement.

But the FDA field inspectors also cited reporting problems with Darvon, Lilly's big-selling painkiller; Fountain added Pergoglide, a drug for breast cancer.

As to Oraflex, Hensley said that a check of 173 adverse-reaction reports submitted to Lilly by five physician-testers showed that the company did not tell the FDA of 65 that turned out to be related to use of the drug. Moreover, he said, the five doctors had discovered but not informed Lilly about 22 additional adverse reactions.

In interviews at Lilly, Hensley wrote, Dr. Harvey Barnett, who had regulatory responsibilities for Oraflex, admitted that he had withheld reports on the 65 cases but "could offer no explanations."

Helmsley also said that Barnett and two other Lilly employes, Dr. Frank Peck, director of regulatory affairs, and JoAnn Muller, senior regulatory reports coordinator, all agreed that the selective nature of the reporting of adverse reactions in the marketing application for Oraflex "is typical of all" such applications made by Lilly.