|AHFS/Drugs.com||International Drug Names|
|Intravenous and intramuscular|
|Metabolism||Hepatic to valdecoxib and propionic acid|
CYP extensively involved (mainly CYP3A4 and 2C9)
|Elimination half-life||22 minutes (parecoxib)|
8 hours (valdecoxib)
|Excretion||Renal (70%, metabolites)|
|CompTox Dashboard (EPA)|
|Chemical and physical data|
|Molar mass||370.422 g/mol g·mol−1|
|3D model (JSmol)|
|(what is this?)|
Parecoxib, sold under the brand name Dynastat among others, is a water-soluble and injectable prodrug of valdecoxib. Parecoxib is a COX2 selective inhibitor. It is injectable. It is approved through much of Europe for short term perioperative pain control.
It was patented in 1996 and approved for medical use in 2002.
In 2005, the U.S. Food and Drug Administration (FDA) issued a letter of non-approval for parecoxib in the United States. No reasons were ever documented publicly for the non-approval, although one study noted increased occurrences of heart attacks following cardiac bypass surgery compared to placebo when high doses of parecoxib were used to control pain after surgery. It is also important to remember that rare but severe allergic reactions (Stevens-Johnson Syndrome, Lyell syndrome) have been described with valdecoxib, the molecule to which parecoxib is converted. The drug is not approved for use after cardiac surgery in Europe.
All anti-inflammatory medications in the U.S. carry the same warning regarding skin reactions, and none are approved for use during CABG surgery, so the reason for the FDA denying the approval of parecoxib remains unknown, but was likely related to political pressure from the US Congress to not approve another COX-2 selective inhibitor in the wake of the Vioxx affair. No COX-2 selective inhibitor has been approved in the US since that time, regardless of the safety profile of parecoxib in Europe. Efforts to find out the scientific rationale, or more likely the lack thereof, that the FDA used to justify the non-approval of parecoxib in the USA have proven futile due to secrecy issues.
The political motivation to not approve parecoxib was further supported by a 2017 pooled analysis of safety data in 28 published studies, which showed after 69,567,300 units of parecoxib, skin rash and cardiac complications were minimal, if at all, different from placebo.