Walgreen Co, the largest U.S. drug store chain, has agreed to pay $80 million in civil penalties to resolve allegations that it violated federal rules that govern how prescription drug painkillers, including oxycodone, are distributed.

The Walgreens drug settlement of $80 million is the largest civil penalty paid under the Controlled Substances Act in DEA history, topping the $34 million shelled out by Cardinal Health Inc. in 2008. The Walgreens record-keeping violations allowed millions of oxycodone pills to reach the prescription drug black market in the U.S.

As part of the settlement, DEA suspended the Walgreens drug distribution center for two years.

The DEA said Walgreens failed to maintain proper controls to ensure it did not dispense drugs to addicts and drug dealers. Six of Walgreens' Florida pharmacies ordered more than a million pills a year, the DEA said. In 2011, the average pharmacy in the U.S. ordered 73,000 oxycodone tablets a year.

One pharmacy in Fort Myers went from ordering 95,800 pills in 2009 to 2.2 million pills in 2011, the DEA said. Another pharmacy in Hudson, a town of 34,000 people near Clearwater, purchased 2.2 million pills in 2011, the DEA said.

"Walgreens pharmacists blatantly ignored red flags," Miami field district Special Agent in Charge Mark Trouville said.

In 2008 Cardinal Health Inc., one of the nation's largest distributors of pharmaceutical drugs, has agreed to settle allegations that it violated federal reporting provisions relating to its handling of certain controlled substances regulated by the Drug Enforcement Administration.

Under the agreement between the company and seven U.S. Attorney's Offices, Cardinal Health agreed to pay $34,000,000 in civil penalties for alleged violations of its obligations under the Controlled Substances Act.

Cardinal Health, which operates 27 DEA-registered distribution facilities, failed to report to DEA suspicious orders of hydrocodone that it then distributed to pharmacies that filled illegitimate prescriptions originating from rogue Internet pharmacy Web sites. These prescriptions violated applicable Federal and State law because they were not issued for a legitimate medical purpose by physicians acting within the usual course of professional practice.