"The percentage of deaths with concomitant involvement of other drugs varied by drug. For example, almost all drug overdose deaths involving alprazolam or diazepam (96%) mentioned involvement of other drugs. In contrast, 50% of the drug overdose deaths involving methamphetamine, and 69% of the drug overdose deaths involving fentanyl mentioned involvement of one or more other specific drugs.

"Table D shows the most frequent concomitant drug mentions for each of the top 10 drugs involved in drug overdose deaths in 2016.

"For the top 15 drugs:

"• Among drug overdose deaths that mentioned at least one specific drug, oxycodone ranked first in 2011,heroin from 2012 through 2015, and fentanyl in 2016.

"• In 2011 and 2012, fentanyl was mentioned in approximately 1,600 drug overdose deaths each year, but mentions increased in 2013 (1,919 deaths),2014 (4,223 deaths), 2015 (8,251 deaths), and 2016(18,335 deaths). In 2016, 29% of all drug overdose deaths mentioned involvement of fentanyl.

"The number of drug overdose deaths per year increased 54%, from 41,340 deaths in 2011 to 63,632 deaths in 2016 (Table A). From the literal text analysis, the percentage of drug overdose deaths mentioning at least one specific drug or substance increased from 73% of the deaths in 2011 to 85% of the deaths in 2016. The percentage of drug overdose deaths that mentioned only a drug class but not a specific drug or substance declined from 5.1% of deaths in 2011 to 2.5% in 2016.

"• The rate of drug overdose deaths involving synthetic opioids other than methadone, which include drugs such as fentanyl, fentanyl analogs, and tramadol, increased from 0.3 per 100,000 in 1999 to 1.0 in 2013, 1.8 in 2014, 3.1 in 2015, 6.2 in 2016, and 9.0 in 2017 (Figure 4). The rate increased on average by 8% per year from 1999 through 2013 and by 71% per year from 2013 through 2017.

"• The rate of drug overdose deaths involving heroin increased from 0.7 in 1999 to 1.0 in 2008 to 4.9 in 2016. The rate in 2017 was the same as in 2016 (4.9).

"The overall mortality rate for unintentional drug poisonings in the United States grew exponentially from 1979 through 2016. This exponentially increasing mortality rate has tracked along a remarkably smooth trajectory (log linear R2 = 0.99) for at least 38 years (left panel). By contrast, the trajectories of mortality rates from individual drugs have not tracked along exponential trajectories. Cocaine was a leading cause in 2005–2006, which was overtaken successively by prescription opioids, then heroin, and then synthetic opioids such as fentanyl.

According to the Centers for Disease Control, using data available for analysis on September 5, 2018, there were a reported 70,652 deaths attributed to drug overdose in the US for the year ending December 2017. Some deaths were still under investigation. The CDC projects that the total for 2017 will be 72,222.

"In the 12 months after a nonfatal overdose, 2040 persons (11%) enrolled in MMT for a median of 5 months (interquartile range, 2 to 9 months), 3022 persons (17%) received buprenorphine for a median of 4 months (interquartile range, 2 to 8 months), and 1099 persons (6%) received naltrexone for a median of 1 month (interquartile range, 1 to 2 months). Among the entire cohort, all-cause mortality was 4.7 deaths (95% CI, 4.4 to 5.0 deaths) per 100 person-years and opioid-related mortality was 2.1 deaths (CI, 1.9 to 2.4 deaths) per 100 person-years.

"Vulnerability to Opioid Overdose

"Among the 42 249 opioid-related overdose deaths in 2016, 19,413 involved synthetic opioids, 17,087 involved prescription opioids, and 15,469 involved heroin. Synthetic opioid involvement in these deaths increased significantly from 3007 (14.3% of opioid-related deaths) in 2010 to 19,413 (45.9%) in 2016 (P for trend <.01). Significant increases in synthetic opioid involvement in overdose deaths involving prescription opioids, heroin, and all other illicit or psychotherapeutic drugs were found from 2010 through 2016 (Table).

"The use of MC [Medical Cannabis] as an alternative to POMs [Prescription Opioid Medications] for pain management warrants additional empirical attention as a potential harm reduction strategy. NASEM (2017) recommends more clinical trials to elucidate appropriate MC forms, routes of administration, and combination of products for treating pain, but access to MC products to fully evaluate these questions is challenging due to federal regulations.