Parecoxib
Systematic (IUPAC) name
N-{[4-(5-methyl-3-phenylisoxazol-4-yl)phenyl] sulfonyl}propanamide
Identifiers
CAS number	202409-33-4
ATC code	M01AH04
PubChem	119828
Chemical data
Formula	C19H18N2O4S
Mol. mass	370.422 g/mol
Pharmacokinetic data
Bioavailability	100%
Protein binding	98%
Metabolism	Hepatic to valdecoxib and propionic acid CYP extensively involved (mainly CYP3A4 and 2C9)
Half life	22 minutes (parecoxib) 8 hours (valdecoxib)
Excretion	Renal (70%, metabolites)
Therapeutic considerations
Licence data	EU
Pregnancy cat.	Not recommended
Legal status	POM(UK)
Routes	Intravenous and intramuscular

Parecoxib is a water soluble and injectable prodrug of valdecoxib. It is marketed as Dynastat in the European Union. Parecoxib is a COX2 selective inhibitor in the same category as celecoxib (Celebrex) and rofecoxib (Vioxx). As it is injectable, it can be used perioperatively when patients are unable to take oral medications. It is approved through much of Europe for short term perioperative pain control much in the same way ketorolac (Toradol) is used in the United States. However, unlike ketorolac, parecoxib has no affect on platelet function and therefore does not promote bleeding during or after surgery. In addition, ketorolac has a much higher gastrointestinal toxicity profile compared to most other nonsteroidal antiinflammatory drugs (NSAIDs) including ibuprofen and naprosyn. However, in the United States ketorolac is the only injectable NSAID, although it is banned in many European countries due to concerns about surgical bleeding and stomach ulcers after surgery.

In 2005, the 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 in which parecoxib is converted ¹ . The drug is not approved for use after cardiac surgery in Europe. Ketorolac, still banned in much of Europe, is therefore the only option in the United States, and it is not clear whether parecoxib will be resubmitted to the FDA in the future.

See also

• COX-2 selective inhibitor
• Cyclooxygenase 2 inhibitors: drug discovery and development

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