"Selective" switching from non-selective to selective non-steroidal anti-inflammatory drugs.
BACKGROUND
Non-steroidal anti inflammatory drugs (NSAIDs) are thought to account for almost 25% of all reported adverse drug reactions, primarily gastrointestinal (GI) toxicity. Selective cyclo-oxygenase-2 (COX-2) inhibitors have been shown to preferentially inhibit activity of the COX-2 enzyme, which maintains anti-inflammatory activity but reduces GI toxicity.


OBJECTIVE
To determine the degree of switching from non-selective NSAIDs to COX-2 inhibitors and to examine the factors that were associated with switching.


METHODS
The General Medical Services prescription database (1.2 million people) was examined for NSAID prescriptions from December 1999 through November 2001. All those receiving non-selective NSAIDs and those switching to selective COX-2 inhibitors after at least 1 month on a non-selective NSAID were identified (non-switchers and switchers, respectively). Age, sex, dose of non-selective NSAID and co-prescribing of anti-peptic ulcer (anti-PU) drugs were considered between switchers and non-switchers, and odds ratios (OR) calculated using logistic regression. The effect of chronic use (> or =3 months prescription of a non-selective NSAID during the study period) on switching was also evaluated.


RESULTS
A total of 81,538 of 480,573 patients (17%) initially prescribed non-selective NSAIDs were switched to COX-2 inhibitors during the study. The elderly (65 years or older) were more likely to be switched to a COX-2 inhibitor [OR=1.81, 95% confidence interval (CI) 1.79, 1.84]. Women were also more likely to be switched to COX-2 inhibitor therapy (OR=1.25, 95% CI 1.23, 1.27). Previous but not subsequent prescribing of anti-PU drugs was also associated with switching. Chronic users showed similar switching patterns.


CONCLUSIONS
Prescribers are more likely to switch older female patients and those with a past history of peptic ulcers from non-selective NSAIDs to COX-2 inhibitors. This suggests that doctors take risk factors into consideration when prescribing NSAIDs. The relatively low rate of switching may suggest that prescribers still have concerns over the place of COX-2 inhibitors and reserve their use to those patients particularly at risk of NSAID-induced GI toxicity.
Bennett
Kathleen
K
Department of Pharmacology and Therapeutics, Trinity College/St James's Hospital, Dublin 8, Ireland. bennettk@tcd.ie
Teeling
Mary
M
Feely
John
J
D000367:Age Factors; D000368:Aged; D000894:Anti-Inflammatory Agents, Non-Steroidal / Q000008:administration & dosage* / Q000009:adverse effects; D051546:Cyclooxygenase 2; D052246:Cyclooxygenase 2 Inhibitors; D016861:Cyclooxygenase Inhibitors / Q000008:administration & dosage* / Q000009:adverse effects; D011307:Drug Prescriptions; D004363:Drug Utilization; D005260:Female; D006801:Humans; D007527:Isoenzymes / Q000037:antagonists & inhibitors*; D008297:Male; D008565:Membrane Proteins; D011451:Prostaglandin-Endoperoxide Synthases; D012189:Retrospective Studies; D012737:Sex Factors
D000894:Anti-Inflammatory Agents, Non-Steroidal; D052246:Cyclooxygenase 2 Inhibitors; D016861:Cyclooxygenase Inhibitors; D007527:Isoenzymes; D008565:Membrane Proteins; D051546:Cyclooxygenase 2; C496540:PTGS2 protein, human; D011451:Prostaglandin-Endoperoxide Synthases