We have a solution for the opioid epidemic. It’s dramatically underused.

Medications work really well for opioid addiction. Most rehab facilities don’t use them.

Ian McLoone was at his son’s first birthday party in 2011 when his drug addiction rehab center called him at his Minneapolis home, telling him he needed to come back early.

McLoone quickly realized he was in trouble. The day before, he had missed curfew while chaperoning another client’s family visit for the inpatient facility. After the call, McLoone told his family that he had to go, and left, embarrassed. Over the next few days, he would...