“As drug overdose deaths continue their record climb, Missouri last month became the 50th state to launch a prescription drug monitoring program, or PDMP. These state-run databases, which track prescriptions of certain potentially addictive or dangerous medications, are widely regarded as an essential tool to stem the opioid epidemic. Missouri Gov. Eric Greitens last month announced he was creating one in what had been the lone holdout state; legislative efforts to establish a program there had repeatedly failed because of lawmakers’ concerns about privacy.”