The maker of Botox, Allergan, has agreed to pay $600 million to settle charges which it illegally promoted and sold through the year 2005 for unapproved uses like treating headaches.

The settlement, the latest in a continuing justice department crackdown on off-label drug promotion carried out by pharmaceutical companies, comes with an unusual postscript.

In the last few months the Food and Drug Administration (FDA) has been seriously analyzing the approval of Botox for the treatment of chronic migraines. It is a remedy which has been cited as beneficial in new studies and which was corrected last month in UK.

Before the FDA’s review, the charges of illegal marketing cover the first half of this decade. The company initiated a wide-ranging marketing program as per the complaint. The complaint included paying doctors with kickbacks to make them prescribe Botox for conditions not included in the drug’s label.

Department of Justice Assistant Attorney General Tony West told reporters: “Allergan also taught doctors how to bill for off-label uses, including coaching doctors on how to miscode Botox claims, leading to millions of dollars of false claims being submitted to federal and state government programs.”