Use of prescription drugs represents a major healthcare expense in the United States, and the number of adults taking prescription medications continues to increase. Researchers from the Harvard T.H. Chan School of Public Health examined trends in prescription drug use from 1999-2012 using data from nearly 40,000 adults, 20 years and older, who participated in the National Health and Nutrition Examination Survey. They found that the prevalence of prescription drug use increased from 51 percent in 1999-2000 to 59 percent in 2011-2012, while the use of five or more prescription drugs increased from 8 percent to 15 percent.

Eight of the ten most commonly used drugs in 2011-2012 are used to treat components of the cardiometabolic syndrome, including high blood pressure, diabetes, and high cholesterol. Researchers note that the increase in use of several medications may reflect the growing need to treat obesity related complications. Use of antidepressants also increased from 7 percent in 1999-2000 to 13 percent in 2011-2012. The most commonly used individual drug was simvastatin, a medication used to treat high cholesterol. Simvastatin was used by 8 percent of the adult population in 2011-2012, up from 2.0 percent in 1999-2000.