Bloomberg and Reuters reported Wednesday that the US and several states have filed a complaint against Novartis that says the company paid kickbacks to specialty pharmaceutical company BioScrip for amping up patient refills of the drug Exjade, which is used to tamp down iron levels caused by blood transfusions.

The US says the alleged kickback scheme started in 2007, just as Novartis was getting worried that patients would stop taking the drug because of side effects such as a potential for kidney and liver failure. Bloomberg notes that BioScrip is accused of calling patients to convince them to keep taking the drug between 2007 and 2012, and federal and state official say the promotion put Medicare and Medicaid programs on the hook for tens of millions of dollars in reimbursements based on false drug claims.

Novartis told Bloomberg it disputes the allegations.