The scourge of the opioid crisis in the United States kills 90 Americans every day, but beyond the human toll it also handicaps the US economy, taking millions of people out of the workforce, economists warn.

President Donald Trump has declared the epidemic a national emergency, as 2.4 million Americans are estimated to be addicted to opiates, the narcotics that include prescription painkillers such as morphine, as well as heroin.

Trump's Council of Economic Advisers estimates that in 2015 the opioid crisis cost the US economy $504 billion, or 2.8 percent of gross domestic product, in increased healthcare costs and lost wages, far higher than previously estimated.

More than 50,000 Americans died from a drug overdose in 2015, more than half of which were due to opiates, the CEA said in a report published November 20.