National trends in use of medications in office-based practice, 1985-1999.

Increases in physician office visits involving the use or prescribing of a drug were observed between 1985 and 1999 using data from the National Ambulatory Medical Care Survey. The prescription rate increased from 109 to 146 prescriptions per 100 visits. Growth in drug mention rates for specific therapeutic classes varied by patients' age. The rate of multiple prescriptions per visit rose 39 percent. Similar-size increases were observed after differences in patients' age, number of comorbidities, source of payment, and physician specialty were controlled for.