U.S. Sen. Charles Grassley, an Iowa Republican, requested data from each state this year listing which doctors write the most prescriptions for eight common drugs covered by Medicaid, the federal health program for the poor. The reports were intended to “ensure that taxpayer dollars are appropriately spent,” Grassley wrote in a letter to state officials. The report detailed the top prescribers of the following drugs:Abilify, Geodon, Oxycontin, Risperdal, Roxicodone, Seroquel, Xanax, Zyprexa. Among the doctors getting the most reimbursements were a Columbia psychiatrist who wrote about 3,900 prescriptions for the drugs in question in 2008 and 2009. The doctor billed about $1.3 million to Medicaid, according to a Post and Courier review of the data.