Trends in outpatient prescription drug use and related costs in the US: 1998-2003.

Objective: To present a brief synopsis of trends in the number of prescriptions and retail costs of outpatient drugs dispensed in the US between 1998 and 2003.

Methods: Data were extracted from IMS Health, the National Prescription Audit Plus and the National Disease and Therapeutic Index databases.

Results: In 1998, 2.7 billion outpatient prescriptions were dispensed versus 3.6 billion in 2003. This equates to a 33.3% increase over the 6-year period. Of the top 20 most dispensed drugs by volume, 40% were launched in the 1990s or 2000s. Retail costs for the total market of dispensed outpatient prescription drugs were 96.1 billion US dollars in 1998 and 196 billion US dollars in 2003, a 104% increase. Of the top 20 most dispensed drugs by retail cost, all were tradename drugs and were launched in the 1990s or 2000s.

Conclusions: These data indicate a large increase in the US over a short time period in dispensed outpatient prescriptions and their associated retail costs.