A recent report by the Centers for Disease Control and Prevention shows that drug overdose deaths nearly tripled during 1999–2014. Among 47,055 drug overdose deaths that occurred in 2014 in the United States, nearly 30,000 of these deaths involved an opioid. There are now more people killed by opioids than from bullets.
[Update March 16, 2017] The Commission on Narcotic Drugs, part of the UN, has decided to help the US by adding two chemicals, used to make the drug Fentanyl, to an international list of controlled substances. It is hoped that it will help fight a wave of deaths by overdose in America. The substances are two precursors of Fentanyl, 4-anilino-N-phenethylpiperidine (ANPP) and N-phenethyl-4-piperidone (NPP). It also added a fentanyl analog called butyrfentanyl, a drug similar to fentanyl.
 Rose et al: Increases in Drug and Opioid-Involved Overdose Deaths — United States, 2010–2015 in Morbidity and Mortality Weekly Report (MMWR) – 2016
 Washington Post: Heroin deaths surpass gun homicides for the first time, CDC data shows – 2016. See here.