President-elect Ronald Reagan's closest friend on Capitol Hill strongly favors a Carter administration effort to help state governments, hospitals and pharmacists shave the prices of prescription medicines. But the same effort has been condemned by Reagan's health advisers in a report to the presidential transition team.

Sen. Paul Laxalt (R-Nev.) protested delays in issuing a Food and Drug Administration list enabling buyers of more than 5,000 prescription drug products to cut costs by buying often less costly "therapeutic equivalents" of trade-name versions.

For example, a separate document gives the price to the pharmacist of four 25-milligram capsules (the usual daily dosage) of a popular tranquilizer as 50.9 cents to 61.8 cents under the widely promoted Roche Laboratories trade name of Librium. But, says the "Guide to Prescription Drug Costs," published by the Health Care Financing Administration, the price is only 6.6 cents to 17.6 cents under such names as apoxide, chlordiazachel and SK-Lygen, used by 30 other suppliers. The FDA has approved the generic brands as well as Librium as safe and effective for their intended uses.

Laxalt, in a letter to FDA Commissioner Jere E. Goyan Aug. 4, while he was Reagan's campaign manager, recalled that the list had been set for release early this year. The FDA didn't publish it until Oct. 30.

Relying on the early release date, the Nevada legislature passed a law requiring pharmacists to consult the list and allowing them to substitute lower-cost, therapeutically equivalent drugs when a physician writes a prescription for a more expensive version. All of the states except Indiana and Texas permit or require such substitution unless the physician specifies that the best interests of the patient require a higher-priced drug.

The months-long delay in publication postponed the effective date of the Nevada law, "costing Nevada consumers thousands of dollars in unnecessary drug costs," Laxalt told Goyan.

In releasing the list, which the agency first proposed last year, Goyan termed it "a milestone in government efforts to lower the cost of health care." t

That's not the view of the Health Policy Advisory Group (HPAG), which was formed last May at Reagan's personal request by Dr. William B. Walsh, president of Project Hope. In a recent interview, Walsh told a reporter that HPAG urged publication of the list be halted on the ground that it is "costly, undocumented, opinionated and assumed to be without legal authority."

The Pharmaceutical Manufacturers Association, whose members make more than 90 percent of the nation's prescription drugs, is a long-time foe of the list project. HPAG's 16 members included former PMA president C. Joseph Stetler, Allergan Pharmaceuticals senior vice president James H. Cavanaugh, and Upjohn Co. executive vice president Theodore Cooper. Several other HPAG recommendations to the transition team, headed by Robert Carleson, a Californian who served under Reagan when he was governor, constituted what an FDA source termed an industry "wish list."