Medication therapy in ambulatory medical care: United States, 2003-04.

Objective: This report describes medication therapy at visits to physician offices, hospital outpatient departments, and emergency departments in the United States during 2003 and 2004. Office-based care is further subdivided into three categories-primary care, surgical specialties, and medical specialties.

Methods: Data from the 2003 and 2004 National Ambulatory Medical Care Surveys (NAMCS) and National Hospital Ambulatory Medical Care Surveys (NHAMCS) were combined to produce averaged annual estimates of ambulatory medical care utilization.

Results: An estimated 1.9 billion drugs per year were provided, prescribed, or continued at ambulatory care visits in the United States during 2003 and 2004. Two-thirds of the 1.1 billion ambulatory care visits per year included medication therapy. The rate was highest at visits to medical specialists (2.3 drugs per visit). The rate of drugs per visit increased with patient age in each ambulatory care setting. Cardiovascular-renal was the class of drugs most frequently cited at visits to primary care physicians and medical specialists. Pain relievers were the drugs reported most often at hospital emergency and outpatient department visits. Of the 50 drugs most frequently reported overall, three-quarters of them were accounted for by six therapeutic classes-pain relievers, cardiovascular-renal agents, respiratory tract drugs, central nervous system drugs (antianxiety agents and antidepressants), hormonal agents, and antimicrobials. Ibuprofen, aspirin, atorvastatin calcium, acetaminophen, and albuterol were the five most frequently reported medications. From 1993 to 2004, the number of drugs provided, prescribed, or continued per visit increased for all settings.