DOVER — Delaware Auditor Kathy McGuiness on Monday called on Express Scripts Inc. to pay back the $24.5 million she says it overcharged the state of Delaware for its state employees’ prescription drug plan from 2018 through 2020.

“My special report found that Delaware paid three times the average drug inflationary price between 2018 and 2020 for state employee prescriptions,” Ms. McGuiness said in a statement.

“While the national drug inflationary rate was 4.7 percent during those three years, Delaware paid a 20.1 percent increase in prescription costs,” she continued. “That’s an abuse of taxpayer dollars that should be returned to Delawareans.”

Her office released a report titled “Lack of Transparency & Accountability in Drug Pricing Could be Costing Taxpayers Millions” on Friday.

Recommendations in the report include revising contracts to allow full audit rights, adding stronger oversight to prevent pharmacy benefit manager reimbursement, developing “a robust analytics program that reviews prescription drug program data outside of regular periodic audits” and allowing pharmacies to decline to dispense a prescription drug if the amount reimbursed by is less than the pharmacy acquisition cost.

The report can be found here.

Express Scripts did not respond to an email seeking comment Monday.