1. Quickfacts United States. U.S. Census Bureau.http://www.census.gov/quickfacts/fact/table/US/PST045218. Accessed September 14, 2019.
2. Prescription opioid use, misuse, and use disorders in U.S. adults: 2015 National Survey on drug use and health;Han;Ann Intern Med,2017
3. What is polypharmacy? A systematic review of definitions;Masnoon;BMC Geriatr,2017
4. Opioid overdose crisis. NIH, National Institute on Drug Abuse, Advancing Addiction Science.http://www.drugabuse.gov/drugs-abuse/opioids/opioid-overdose-crisis#two. Accessed July 31, 2019.
5. What is the U.S. opioid epidemic?HHS.http://www.hhs.gov/opioids/about-the-epidemic/index.html. Accessed July 31, 2019.