COX-2 inhibitor

COX -2 inhibitor or COX -2 inhibitors (generally coxibs ) refers to a group of anti-inflammatory drugs, in which only one of the forms of cyclooxygenase (COX) is inhibited.

The most important forms of this enzyme are the cyclooxygenase-1 (COX -1) and cyclooxygenase -2 (COX -2). It had been hoped that the COX -2 cause inflammation, while COX -1 is responsible for some major organ functions such as the renal blood flow and protect the stomach lining from stomach acid. But this is not true. Selective COX -2 inhibitors exert their effect primarily on the COX-2 and only a little on the COX-1.

Pros and Cons

Nonsteroidal anti-inflammatory drugs ( NSAIDs), which were used before the discovery of selective COX -2 inhibitor, inhibited both COX -1 and COX -2. With inhibition of COX -2 led to a decrease of inflammation, but also to side effects caused by inhibition of COX-1. In most patients, although showed no measurable organ damage, but it can cause bleeding of the stomach lining and decline in renal function in taking non-selective COX inhibitors.

Taking selective COX -2 inhibitors COX-1 is only slightly affected, but this does not lead to absence of side effects. In licensing and marketing studies mainly lower compared to older NSAIDs rate gastroscopically searchable gastric mucosal damage was shown. The reason for this is that gastric protective operated by COX -1 synthesis of prostaglandins is hardly reduced. The clinical significance of these findings is, however, still unclear.

Side effects

The most common side effects mentioned are: infection of the upper respiratory tract, diarrhea, dyspepsia, abdominal pain, headache. Peripheral edema, increased blood pressure, occur with COX-2 selective nonsteroidal anti-inflammatory drugs as well as often in the case of conventional NSAIDs.

In 2004 arose in the course of study in the U.S. suspected that prolonged ingestion of Vioxx ® ( rofecoxib, a selective COX -2 inhibitor ) increases the risk of heart attack significantly. COX -2 inhibitors decrease the synthesis of prostacyclin, which inhibits platelet aggregation and vasodilatory effect, whereas the COX -1 - mediated formation of functional antagonists, thromboxane (which thus promotes platelet aggregation and vasoconstriction causes ) remains unaffected, so total an increased clotting tendency resulting in narrower vessels. Vioxx ® was therefore withdrawn from the market in September 2004.

In November 2006 came with lumiracoxib, a COX -2 inhibitor on the market, which does not resemble the other coxibs, but diclofenac in structure; if therefore the risk of cardiovascular (heart and vascular system in question ) is less side effects, remained unclear. Due to serious liver damage, the agent has since been taken off the market.

The COX -2 inhibitor valdecoxib has now been taken off the market, the COX -2 inhibitor etoricoxib not approved in the U.S. due to safety concerns. The Related valdecoxib parenteral COX -2 inhibitors parecoxib has been taken off the market in Switzerland due to safety concerns and not approved in the United States.

Allow in vitro data suggest that the anti-inflammatory effect of tocotrienols on the selective inhibition of COX -2 is based.

Available in Germany coxibs

• Celecoxib
• Etoricoxib
• Parecoxib