Etoricoxib


Etoricoxib, sold under the trade name Gencox, is a selective COX-2 inhibitor from McOLSON Research Laboratories. Currently it is approved in more than 80 countries worldwide but not in the US, where the Food and Drug Administration has required additional safety and efficacy data for etoricoxib before it will issue approval.
It was patented in 1996 and approved for medical use in 2002.

Medical uses

Etoricoxib is indicated for the treatment of rheumatoid arthritis, psoriatic arthritis, osteoarthritis, ankylosing spondylitis, chronic low back pain, acute pain, and gout. Approved indications differ by country. In the U.K., it is also "used for the short term treatment of moderate pain after dental surgery" of adults.
A Cochrane review assessed the benefits of single-dose etoricoxib in reduction of acute post-operative pain in adults. Single-dose oral etoricoxib provides four times more pain relief post-operatively than placebo, with equivalent levels of adverse events. Etoricoxib given at a dose of 120 mg is as effective or even better than other analgesics that are commonly used.

Adverse effects

Like all other NSAIDs the COX-2 inhibitors too have their share of adverse effects. Fixed drug eruption and generalised erythema, acute generalized exanthematous pustulosis, erythema multiforme like eruption and drug induced pretibial erythema are some serious side effects reported, besides the usual innocuous ones.

Mechanism of action

Like any other selective COX-2 inhibitor, etoricoxib selectively inhibits isoform 2 of the enzyme cyclooxygenase. It has approximately 106-fold selectivity for COX-2 inhibition over COX-1. This reduces the generation of prostaglandins from arachidonic acid. Among the different functions exerted by PGs, their role in the inflammation cascade should be highlighted.
Selective COX-2 inhibitors show less activity on COX-1 compared to traditional non-steroidal anti-inflammatory drugs. This reduced activity is the cause of reduced gastrointestinal side effects, as demonstrated in several large clinical trials performed with different coxibs.

History

Some clinical trials and meta-analysis showed that treatment with some coxibs led to increased incidence of adverse cardiovascular events compared to placebo. Because of these results, some drugs were withdrawn from the market. In addition, the United States Food and Drug Administration and the European Medicines Agency started revision processes of the entire class of both NSAIDs and COX-2 inhibitors.
In April 2007, the FDA issued Merck a non-approvable letter for etoricoxib. The letter said Merck needs to provide more test results showing that the drug's benefits outweigh its risks before it has another chance of getting approved.

Brand names

Brand names for etoricoxib include: