Prof. Robert Valuck, who runs the Center for Prescription Drug Abuse Prevention at the University of Colorado School of Pharmacy, said Trump's get-tough approach on choking off supply may help reduce deaths, as long as it continues to be accompanied by drug-treatment opportunities.

President Trump has been vocal in his desire to stop fentanyl smuggling, but his budget proposed cuts to drug programs.

The progress comes as the Trump administration is proposing to cut funding for many programs believed to have contributed to the improvement.