The ACA requires drug manufacturers to report the total number of units that are used to calculate the monthly average manufacturer price (AMP) for each covered outpatient drug no later than 30 days after the last day of the month. CMS has updated the Medicaid Drug Data Reporting system to enable reporting of AMP units to CMS for the October 2010 reporting period; October 2010 reports are due by November 30, 2010.