The Food and Drug Administration is advising consumers not to purchase prescription drugs from Web sites that have their orders filled from Canadian companies reportedly selling counterfeit medications.

The FDA is investigating reports that Mediplan Prescription Plus Pharmacy or Mediplan Global Health in Manitoba, Canada sold fake drugs to U.S. consumers.

It is coordinating its efforts with international law enforcement authorities.

The FDA is recommending that consumers who have bought drugs from these Web sites discard the products because they many be unsafe.

Laboratory analyses are underway for intercepted drugs that were destined for the U.S. market.

Preliminary laboratory results found counterfeits of the following drug products: Lipitor, Diovan, Actonel, Nexium, Hyzaar, Ezetrol (known as Zetia in the United States), Crestor, Celebrex, Arimidex, and Propecia.

All of these medications require a prescription from a licensed health care provider to be legally dispensed.

Some of the Web sites that are operated by Mediplan or that have order fulfillment through Mediplan are:

* www.RxNorth.com; * www.Canadiandrugstore.com; * www.Rxbyfax.com; * www.Northcountryrx.com; * www.Canada-pharmacy.com; * www.My-canada-pharmacy.com; * www.NLRX.com; * www.Canampharmacy.com; * www.Canada-Meds-For-Less.net; and * www.Canadian-safe.com

The FDA is advising consumers to use caution when buying medical products online. The agency says in a statement that although a Web site may appear reputable, it may actually operate from outside the U.S. and provide unapproved drugs from unreliable sources.

For example, in August of 2005, the FDA conducted an operation at New York, Miami, and Los Angeles airports which found that nearly half of the imported drugs FDA intercepted from four selected countries were shipped to fill orders that consumers believed they were placing with "Canadian pharmacies."

Of the drugs being promoted as "Canadian," based on accompanying documentation, 85 percent actually came from 27 other countries around the globe. A number of these products also were found to be counterfeit.

The FDA says these results demonstrated that some Internet sites that claimed to be "Canadian" were, in fact, selling drugs of dubious origin, safety and efficacy.