Etoricoxib and diclofenac are associated with similar cardiovascular risks

It's now clear that non-steroidal anti-inflammatory drugs (NSAIDs) that selectively inhibit cyclo-oxygenase-2 (COX 2) are linked to thrombotic cardiovascular events such as heart attack. But experts are still debating whether this risk extends to more traditional NSAIDs. In a pooled analysis from three large clinical trials in patients with arthritis, diclofenac (a traditional drug) had almost identical effects on cardiovascular risk to those of the COX 2 inhibitor etoricoxib. The event rates were 1.24 per 100 patient years for diclofenac and 1.3 for etoricoxib (hazard ratio 0.95 (95% CI 0.81 to 1.11) for etoricoxib v diclofenac). The researchers, who were sponsored by Merck Research Laboratories, conclude that their COX 2 inhibitor is no worse in this respect than diclofenac, and the authors of a linked commentary (pp 1745-7) estimate that both drugs are responsible for about four extra cardiovascular events for every 1000 patients treated for one year.

The two drugs' cardiovascular effects look similar because both suppress prostacyclin, a prostanoid that restrains platelet activation, hypertension, and atherogenesis. Both drugs also both inhibit COX 2, although diclofenac is less selective than etoricoxib. Patients and doctors now need prospective data on other drugs such naproxen and ibuprofen, both of which looked “safer” than diclofenac in observational studies.