Pharmaceutical companies also want to stick with linear barcodes as the basic method for identifying drug products, keeping options open to provide more information through more sophisticated identifiers. FDA currently requires drugs and biological products to have linear bar codes with the product's national drug code (NDC) on their labels, but expiration dates and lot numbers are discretionary.

Wholesalers and retail pharmacists insist that any national drug pedigree system must be electronic. The Healthcare Distribution Management Association (HDMA, Arlington, VA, http://www.nwda.org/), which represents national drug wholesalers, wants FDA to phase in an RFID system using electronic product codes (EPC) and mass serialization at the item level. HDMA opposes two-dimensional bar codes that must be scanned directly; RFID chips can be read remotely, making it unnecessary to open packages to track a product. Wholesalers also are lobbying for national licensing standards to replace multiple state requirements.

Similarly, retailers would like anticounterfeiting initiatives to focus on high-risk products. They advocate broader public education and awareness efforts, and they support stricter licensing requirements for wholesalers by state pharmacy regulators.

Added pressure for action comes from a growing number of states that are adopting their own drug pedigree requirements. Florida enacted a law in 2003 to discourage drug counterfeiting and diversion by requiring wholesalers to provide paper pedigrees for prescription drugs; it becomes fully effective in July 2006. California expects to implement a drug pedigree policy in 2007 or 2008. It envisions an electronic tracking system that can transmit extensive product data on all drugs moving from a manufacturer through final sale to a pharmacy or dispenser.

In addition, major retailers such as Wal-Mart ( http://www.walmart.com/, Bentonville, AR) are requiring suppliers to ship goods with RFID tags to certain warehouses and stores. The program calls for identifiers to be added to pallets and cases, as opposed to individual products, and primarily involves controlled substances in the pharmaceutical field.

Members of Congress also are stepping up involvement in drug security activities. In March, representatives from both sides of the aisle introduced legislation establishing a time frame for phasing in electronic tracking of prescription drugs. A bill sponsored by Rep. Dan Burton (R-IN) requires RFID tracking of the 30 most frequently counterfeited drugs (to be identified by FDA) by Dec. 31, 2007; the provision extends to all drugs by 2011. Legislation proposed this past year by Rep. Steve Israel (D-NY) goes even further in requiring paper pedigrees until RFID technology is fully established.

Several pharmaceutical manufacturers have launched pilot tests of RFID tracking systems, primarily for products targeted by counterfeiters or other illegal operators. Purdue Pharma (Stamford, CT, http://www.pharma.com/) has tested an electronic pedigree system to track and prevent diversion of "OxyContin." Following pilot tests that shipped tagged tablets from manufacturing plant to distributor HD Smith (Springfield, IL, http://www.hdsmith.com/), Purdue plans to fully implement an electronic pedigree program this year.

Pfizer (New York, NY, http://www.pfizer.com/) has been testing RFID tagging of "Viagra" (sildenafil) to gain experience with mass serialization and EPC capabilities. In January, the company announced that it would add RFID–EPC tags to all Viagra distributed in the United States The company acknowledges that this current tagging system may help distributors and pharmacists authenticate genuine product, but it does not have broader track-and-trace capacity because much of the supply chain is not part of the program.

Multiple layers

A system that fully protects the US prescription drug supply from illegal use requires information systems that can read the data on the tags and make it accessible throughout the distribution system. Additional strategies are needed to distinguish genuine from bogus products and prevent tampering, including increased surveillance and enforcement by the government. Manufacturers and other parties are taking these steps to move the process forward.