Two drug distributors accused of selling counterfeit versions of the popular cholesterol-lowering drug Lipitor have agreed to stop doing so.

Lipitor is the most widely prescribed cholesterol-lowering drug in the United States, with 18 million users, and the best-selling prescription drug in the world. Annual worldwide sales of the drug total more than $9 billion.

On Tuesday, Albers Medical Distributors Inc. of Kansas City and Med-Pro Inc. of Lexington, Neb., agreed to a court order barring them from distributing fake Lipitor products.

The products are all but indistinguishable in appearance from the genuine drug but don't have its chemical composition.

It isn't known whether the counterfeits are themselves harmful, but people who have taken them won't receive the cholesterol-lowering benefits the genuine drug provides.

The Food and Drug Administration said that patients who weren't sure whether they had purchased the fake drug should check with their pharmacist.

Albers and Med-Pro said they unknowingly had sold the fake drug and were cooperating with the drug's manufacturer, Pfizer Ireland Pharmaceuticals, and the FDA, which has launched a criminal investigation.

Tuesday's agreement came after Pfizer and its American subsidiary, Pfizer Inc., sued Albers and Med-Pro in U.S. District Court in Kansas City for trademark counterfeiting, infringement and dilution. It remains unknown how much of the counterfeit product was distributed, but Pfizer said that Albers and Med-Pro had sold "substantial quantities."

Pfizer first began investigating a few weeks ago when patients described an unusually bitter taste after taking what they thought was Lipitor. The company notified the FDA, which announced on May 23 that Albers had voluntarily recalled three lots of 90-pill bottles.

On June 3, the FDA issued another recall notice after saying its investigation had turned up additional quantities of the fake drug.

"We have no medical reports to date of anyone that has been affected in a dangerous manner," said FDA spokeswoman Indya Mungo. "But we have had reports from consumers that the pills they bought had a bitter taste or dissolved too quickly."

The FDA has advised consumers and health-care providers to check the packaging carefully before using Lipitor. Consumers with products containing recalled lot numbers should return them to their pharmacies, the agency said.

The product was repackaged by Med-Pro and the labels say "Repackaged by: MED-PRO, Inc. Lexington, NE" in the lower left-hand corner.

Mungo said the FDA's Office of Criminal Investigations was looking into how the fake product had entered the stream of commerce.

Doug Albers, president of Albers, said Albers had bought the allegedly counterfeit products from another company, "which drop-shipped it for us to Med-Pro. So we never saw the product."

Albers referred additional inquiries to the company's lawyer, Cathy J. Dean, who said it had agreed "to cooperate with Pfizer and the FDA in any way we can to determine where these products came from."

Albers is a 27-year-old wholesale distributor that buys from and sells to other wholesalers. The company has notified the six other distributors who purchased the lots in question. It said the fake drugs "represent a potentially significant risk to consumers."

On June 3, the day after it filed suit, Pfizer said it was notifying pharmacists and other health care professionals that drug tablets identified as Lipitor in packages prepared by Med-Pro may be counterfeit.

The company said its own analysis had determined that tablets from Med-Pro packages purporting to contain Lipitor 10mg and 20mg "bear a close resemblance to authentic Lipitor, though they may be slightly thicker."

Pfizer said it does not distribute Lipitor to Med-Pro and has no relationship with the company or with Albers.

The drug maker said it had received "fewer than 10" consumer complaints so far.

In court documents, Pfizer said the unauthorized sale of counterfeit Lipitor "poses an obvious health risk to consumers because there is no way to assure that consumers are receiving a health benefit from the fake product, nor is there any way of knowing what impurities or safety defects the products contain."

Vanessa McGowan, a spokeswoman for Pfizer, said Tuesday's agreement with Albers and Med-Pro "was the first step in the litigation and is a fairly significant achievement."

As part of the agreement, Albers and Med-Pro agreed to produce documents showing from whom they purchased and to whom they sold the allegedly counterfeit drug.

Kansas City lawyer J.R. Hobbs, who represents Med-Pro, said the company was cooperating with the FDA and "takes the position that at no time did it knowingly repackage counterfeit Lipitor."

"Med-Pro doesn't manufacture, alter, own, buy or sell pharmaceuticals," Hobbs said. "It receives delivery of finished products in bulk and then packages them up in bottles and sends them back to the manufacturers, wholesalers, distributors or their customers."

Repackaging companies like Med-Pro typically don't perform analytical chemical testing of drugs if the bulk containers they receive arrive in properly labeled, undamaged containers.

Med-Pro said the Lipitor tablets it had received were the same shape, size and color and had the same markings as actual pharmaceutical samples of Lipitor. Other than the recall, it said, it had no information to indicate the product wasn't manufactured by Pfizer.

Pfizer introduced Lipitor in 1997 and has spent hundreds of millions of dollars promoting it.

To reach Dan Margolies, call (816) 234-7740 or send e-mail to dmargolies@kcstar.com.

Lipitor recall

The fake Lipitor was repackaged by Med-Pro and the labels say "Repackaged by: MED-PRO, Inc. Lexington, NE" in the lower left-hand corner.

The following lots are involved:

• 20722V -- 90-tablet bottles, 10 mg, expiration 09-2004

• 04132V -- 90-tablet bottles, 10 mg, expiration 01-2004

• 16942V -- 90-tablet bottles, 10 mg, expiration 09-2004

• 20842V -- 90-tablet bottles, 10 mg, expiration 09-2004

• 16092V -- 90-tablet bottles, 10 mg, expiration 07-2004

• D270481 -- 90-tablet bottles, 20 mg, expiration date not available

Pfizer has posted a picture of a Med-Pro repackaged Lipitor bottle on its Web site at www.lipitor.com.