Impact of withdrawal from market on the pattern of cyclooxygenase-2 inhibitors reported to Texas poison control centers

The cyclooxygenase-2 (COX-2) inhibitor rofecoxib was withdrawn from the US market on September 30, 2004, and valdecoxib was withdrawn on April 7, 2005. The impact of these actions on COX-2 inhibitor exposures reported to poison control centers was unknown. The objective of this study was to describe the pattern of COX-2 inhibitor exposures reported to Texas poison control centers before and after rofecoxib and valdecoxib were withdrawn. The number of celecoxib, rofecoxib, and valdecoxib exposures reported to Texas poison control centers each month during 1999–2006 was identified and examined for changes over time. Comparisons were made with respect to those exposures reported immediately prior to withdrawal (October 2003–September 2004) and to exposures after withdrawal (April 2005–December 2006). The mean monthly number of reported exposures prior to withdrawal was 18.8 for celecoxib, 20.3 for rofecoxib, 13.3 for valdecoxib, and 51.5 for total COX-2 inhibitors. The mean monthly number of reported exposures after withdrawal was 9.3 for celecoxib, 1.8 for rofecoxib, 1.3 for valdecoxib, and 12.3 for total COX-2 inhibitors, representing declines of 51, 91, 90, and 76%, respectively. The withdrawal of rofecoxib and valdecoxib from the market resulted in a decrease in the number of COX-2 inhibitor exposures reported to Texas poison control centers. However, rofecoxib and valdecoxib exposures continued to be reported for a long time after withdrawal. Reported celecoxib exposures declined even though it was not withdrawn from the market.