The United States has been grappling with a worsening drug epidemic since 1999, fueled primarily by an explosion of opioid use. At first, that drug abuse centered around prescription pain pills, such as Oxycodone, Vicodin or Percocet. In recent years, the death toll has risen sharply, fueled in large part by fentanyl, a synthetic opioid that is relatively cheap to manufacture and distribute. Last year, drug overdoses killed more than twice as many Americans as car crashes. Many drug overdoses are the result of ingesting more than one drug, but experts say fentanyl is often involved.