An observational study of the discrediting of COX-2 NSAIDs in Australia: Vioxx or class effect?

Participants were concessional beneficiary status women from the Older cohort (born 1921-26) of the Australian Longitudinal Study on Women's Health who consented to linkage to Pharmaceutical Benefits Scheme data, with at least one rofecoxib prescription dispensed in the 12 months before rofecoxib withdrawal. A prescription was defined as one dispensing occasion. Women were grouped by rofecoxib pattern of use: continuous (nine or more prescriptions dispensed in the 12 months prior to rofecoxib withdrawal) or non-continuous (eight or less prescriptions dispensed in the 12 months prior to rofecoxib withdrawal) users. Incidence rate per 100,000 person days and incidence risk ratio described uptake of alternate medicines, following rofecoxib withdrawal. Kaplan-Meier curves described differences in uptake patterns by medicine and pattern of rofecoxib use. Patterns of use of COX-2s in the next 100 days after first COX-2 uptake were described.Medicine switches and pattern of medicines uptake differed significantly depending upon whether a woman was a continuous or non-continuous rofecoxib user prior to rofecoxib discrediting. Continuous rofecoxib users overwhelmingly switched to another COX-2 and remained continuing COX-2 users for at least 100 days post-switch.The typical switching behaviour of this group of women suggests that the issues leading to the discrediting of rofecoxib were not seen as a COX-2 class effect by prescribers to this high use group of consumers.NSAIDs (Non-Steroidal Anti-inflammatory Drugs)have been consistently associated with adverse gastrointestinal (GI) and renal effects [1]. Selective COX-2 inhibitors (COX-2s) that promised to minimize adverse GI effects [1] were first marketed in Australia in 1998, and listed on the national medicines subsidy Pharmaceutical Benefits Scheme (PBS) from 2000. While PBS guidelines suggested that COX-2s should be prescribed only to patients with a history of GI disorders, concomitant use of corticosteroids, anti-coag