COX-2 agents, with their perceived reduction in side effects, have contributed substantially to a dramatic increase in NSAIDs (non-steroidal anti-inflammatory drugs) prescription utilization and influenced the way physicians prescribe rheumatology medication, according to research presented this week at the American College of Rheumatology Annual Scientific Meeting in San Antonio, Texas.
Traditional or non-selective NSAIDs, such as diclofenac, piroxicam, ibuprofen and naproxen, are effective inhibitors of the enzyme cyclooxygenase (COX) 1 and 2 and, therefore, able to reduce inflammation and musculoskeletal pain COX-1 enzymes help maintain the body's internal stability; COX 2 enzymes signal pain and inflammation.) However, the inhibition of COX-1 enzyme increases the risk for gastrointestinal complications such as bleeding or ulcers in some patients. In 1999, the first selective COX-2 inhibitor, celecoxib (Celebrex®), appeared on the market, followed by rofecoxib (Vioxx®), and valdecoxib (Bextra®). These COX-2 agents selectively inhibit cyclooxygenase 2, the enzyme responsible for inflammation and pain, thereby reducing the incidence of GI side effects.
Utilizing Redbook source data on prescription sales from independent, chain, supermarket, mass merchandisers and deep discount pharmacies, researchers evaluated the influence of the introduction of these COX-2 inhibitors on the number of overall NSAID prescriptions written between 1998 and 2003. Results indicated that, overall, NSAID therapy prescriptions increased 67.7 percent during the five year period due, in large part, to the availability of COX-2 inhibitors. During the first year following their introduction, these COX-2 agents accounted for more than two thirds of the increase seen in NSAID prescriptions. The percentage of NSAID prescriptions written for COX-2 therapy peaked in 2001, despite the introduction of the third COX-2 inhibitor, valdecoxib (Bextra®), in 2002, but these agents still remained influential on the number of total NSAID prescriptions written. Study results also show that total NSAID prescription costs increased by 1.7 percent to $6.5 billion between 2002 to 2003, although COX- 2 inhibitor retail sales costs increased by 4.1 percent during this same time period.
"The introduction of COX-2 inhibitors has led to an overall increase in NSAID prescribing, with COX-2 inhibitors now representing roughly 44 percent of the total NSAID market.," said Bethany Fedutes, Pharm.D., Clinical Specialist in Drug Information, University of Pittsburgh, Pittsburgh, Pennsylvania, and an investigator in the study. "Although overall NSAID retail sales costs have remained stable for the past two years, the percent of COX-2 inhibitor retail sales costs have increased disproportionately to the nonselective NSAIDs."
The American College of Rheumatology is the professional organization for rheumatologists and health professionals who share a dedication to healing, preventing disability and curing arthritis and related rheumatic and musculoskeletal diseases.
For more information on the ACR's annual meeting, see http://www.rheumatology.org/annual.