"Drugs in the United States generally do not travel straight from the line of production to the dispensing pharmacy. Rather, a serpentine maze provides a ripe environment for the infiltration of counterfeit, adulterated, and diverted drugs.15

"The distribution system is primarily tiered among manufacturers, the “Big 3” distributors/drug wholesalers, secondary wholesalers,16 and repackagers. The FDA has identified three primary routes for drug sales in the United States, and each involves drugs passing through multiple hands, demonstrating the vulnerability of the distribution system to counterfeit, adulterated, and diverted products.17 The “Big 3” wholesalers—Cardinal Health,18 McKesson19 and Amerisource Bergen,20 which collectively account for nearly 90% of the primary wholesale arket21—sell drugs into a distribution web containing large governmental agencies, secondary wholesalers, and criminal actors.22 “Repackagers” of drugs further obscure the origin of a particular drug when they break wholesale drugs in bulk containers into smaller units for sale to pharmacies or, conversely, re-aggregate smaller units purchased as overstock from pharmacies into larger bundles for resale to wholesalers.23 Because of the multiple distributors and the repackaging, the true origin of drugs in this net remains obscure.24"

Source

Aleong, Stephanie Feldman, "Green Medicine: Using Lessons From Tort Law and Environmental Law to Hold Pharmaceutical Manufacturers and Authorized Distributors Liable for Injuries Caused by Counterfeit Drugs," University of Pittsburgh Law Review (Pittsburgh, PA: Winter 2007) Volume 69, Issue 2, p. 248-250.
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