indication

For the treatment of rheumatoid arthritis, osteoarthritis, ankylosing spondylitis, chronic low back pain, acute pain and gout.

pharmacology

Etoricoxib is a COX-2 selective inhibitor (approximately 106 times more selective for COX-2 inhibition over COX-1). Currently it is approved in more than 60 countries worldwide but not in the US, where the Food and Drug Administration (FDA) require additional safety and efficacy data for etoricoxib before it will issue approval.

mechanism of action

Like any other COX-2 selective inhibitor Etoricoxib selectively inhibits isoform 2 of cyclo-oxigenase enzyme (COX-2). This reduces prostaglandins (PGs) generation from arachidonic acid.

toxicity

This reduced activity is the cause of reduced gastrointestinal toxicity, as demonstrated in several large clinical trials performed with different COXIB (see below links on NEJM and The Lancet). Some clinical trials and meta-analysis showed that treatment with COXIB lead to increased incidence of cardiovascular adverse events compared to placebo

biotransformation

Hepatic, primarily via CYP3A4.

absorption

Bioavailability is 100% following oral administration.

half life

22 hours

drug interactions

Acenocoumarol: Etoricoxib may increase the anticoagulant effect of acenocoumarol.

Anisindione: Etoricoxib may increase the anticoagulant effect of anisindione.

Dicumarol: Etoricoxib may increase the anticoagulant effect of dicumarol.

Ethinyl Estradiol: Etoricoxib may increase the levels of ethinyl estradiol.

Lithium: Etoricoxib increases serum levels of lithium

Rifampin: Rifampin reduces levels and efficacy of etoricoxib

Warfarin: Etoricoxib may increase the anticoagulant effect of warfarin.