Paroxib powder

Parecoxib is a prodrug of valdecoxib, and valdecoxib is a selective COX-2 inhibitor within the clinical dose range. Cyclooxygenase is the enzyme responsible for making prostaglandins. Two forms of it have been identified, COX-1 and COX-2.

COX-2 is the form that has been shown to be induced by pro-inflammatory stimuli. It has been postulated to be mainly responsible for making the prostanoid mediators of pain, inflammation and fever. COX-2 is also involved in ovulation, implantation and closure of the ductus arteriosus, and in regulation of renal function. It has a part in central nervous system functions too (fever induction, pain perception and cognitive function). It may also play a role in ulcer healing. COX-2 has been identified in the tissue around gastric ulcers in man, but its relevance to ulcer healing has not been established.

Some COX-1 inhibiting NSAIDs and the COX-2 selective inhibitors differ in their antiplatelet activity, and this difference may be of clinical significance in patients at risk of thrombo-embolic reactions. COX-2 selective inhibitors reduce the formation of systemic (and therefore possibly endothelial) prostacyclin without affecting platelet thromboxane. The clinical relevance of these observations has not been established.

Parecoxib is suspected to cause serious birth defects when it is administered during the last trimester of pregnancy. Like other medicines known to inhibit prostaglandin, it may cause premature closure of the ductus arteriosus or uterine inertia. NSAID use in the second or third trimester may cause foetal renal dysfunction, and in severe cases this can lead to a reduction in amniotic fluid volume or oligohydramnios. These effects may appear shortly after treatment starts and are usually reversible. Pregnant women on NSAIDs should be closely monitored for amniotic fluid volume. Parecoxib is contraindicated in the third trimester of pregnancy. Administration of a single dose of parecoxib to lactating women after caesarean section led to a relatively small amount of parecoxib and its active metabolite valdecoxib passing into human milk. This gave a low relative dose for the infant (approximately 1% of the weight-adjusted maternal dose). Parecoxib must not be administered to women who breast-feed.

When people have taken too much Parecoxib, the adverse reactions reported are the same ones that have also been described with the recommended doses. If an overdose happens, the patient is managed with symptomatic and supportive care. Haemodialysis does not remove valdecoxib, and diuresis or alkalisation of the urine may not help either, because valdecoxib is highly bound to protein.

Store Parecoxib below 30°C, and keep it away from light and moisture. Keep it out of the reach of children.