Newswise — Insurers and consumers spent $52.2 billion on prescription drugs in 2008 for outpatient treatment of metabolic conditions such as diabetes and elevated cholesterol, according to the latest News and Numbers from the Agency for Healthcare Research and Quality (AHRQ). Metabolic medicines were the class of drugs with the highest level of spending in 2008.

According to data from the federal agency, purchases of metabolic drugs by adults age 18 and older accounted for 22 percent of the nearly $233 billion spent overall to buy prescription medicines in 2008.

Ranked by total spending, the four remaining top therapeutic classes of outpatient prescription drugs in 2008 were :

• Central nervous system drugs, used to relieve chronic pain and control epileptic seizures and Parkinson's Disease tremors – $35 billion. • Cardiovascular drugs , including calcium channel blockers and diuretics – $29 billion. • Antacids, antidiarrheals, and other medicines for gastrointestinal conditions -- $20 billion. • Antidepressants, antipsychotics and other psychotherapeutic drugs – $20 billion.

Overall purchases of these five therapeutic classes of drugs totaled nearly $156 billion, or two-thirds of the almost $233 billion that was spent on prescription medicines used in the outpatient treatment of adults.

AHRQ, which is part of the U.S. Department of Health and Human Services, improves the quality, safety, efficiency, and effectiveness of health care for all Americans. The data in this AHRQ News and Numbers summary are taken from the Household and Pharmacy Components of the 2008 Medical Expenditure Panel Survey (MEPS), a detailed source of information on the health services used by Americans, the frequency with which they are used, the cost of those services, and how they are paid. For more information, go to the statistical brief: Expenditures for the Top Five Classes of Outpatient Prescription Drugs, Adult ages 18 and Older, 2008 (http://www.meps.ahrq.gov/mepsweb/data_files/publications/st313/stat313.pdf).