Parecoxib is a prodrug of valdecoxib. Valdecoxib is a selective COX-2 inhibitor within the clinical dose range. Cyclooxygenase is responsible for generation of prostaglandins. Two isoforms, COX-1 and COX-2, have been identified. COX-2 is the isoform of the enzyme that has been shown to be induced by pro-inflammatory stimuli and has been postulated to be primarily responsible for the synthesis of prostanoid mediators of pain, inflammation, and fever. COX-2 is also involved in ovulation, implantation and closure of the ductus arteriosus, regulation of renal function, and central nervous system functions (fever induction, pain perception and cognitive function). It may also play a role in ulcer healing. COX-2 has been identified in tissue around gastric ulcers in man but its relevance to ulcer healing has not been established.

The difference in antiplatelet activity between some COX-1 inhibiting NSAIDs and COX-2 selective inhibitors 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.

For the short-term treatment of postoperative pain in adults. The decision to prescribe a selective cyclooxygenase-2 (COX-2) inhibitor should be based on an assessment of the individual patient's overall risks

Adult: The recommended dose is 40 mg administered intravenously (IV) or intramuscularly (IM), followed every 6 to 12 hours by 20 mg or 40 mg as required, not to exceed 80 mg/day. As the cardiovascular risk of COX-2 specific inhibitors may increase with dose and duration of exposure, the shortest duration possible and the lowest effective daily dose should be used. There is limited clinical experience with Parecoxib treatment beyond three days.

Elderly: No dose adjustment is generally necessary in elderly patients (≥65 years). However, for elderly patients weighing less than 50 kg, treatment should be initiated with half the usual recommended dose of Parecoxib and reduce the maximum daily dose to 40 mg.

Children: The safety and efficacy of parecoxib in children under 18 years old have not been established. No data are available. Therefore, parecoxib is not recommended in these patients.

Administration

The IV bolus injection may be given rapidly and directly into a vein or into an existing IV line. The IM injection should be given slowly and deeply into the muscle. For instructions on reconstitution of the medicinal product before administration. Precipitation may occur when Parecoxib is combined in solution with other medicinal products and therefore Parecoxib must not be mixed with any other medicinal product, either during reconstitution or injection. In those patients where the same IV line is to be used to inject another medicinal product, the line must be adequately flushed prior to and after Parecoxib injection with a solution of known compatibility.

Hypersensitivity to the active substance or to any of the excipients.

Commonside effects are-

• Change in your blood pressure (up or down)
• You may get back pain
• Ankles, legs and feet may swell (fluid retention)
• You may feel numb- your skin may lose sensitivity to pain and touch
• You may get vomiting, stomach ache, indigestion, constipation, bloating and wind
• Tests may show abnormal kidney function
• You may feel agitated or find it hard to sleep
• Dizziness
• There is a risk of anaemia- changes in red blood cells after an operation that may cause fatigue and breathlessness
• You may get a sore throat or difficulty breathing (shortness of breath)
• Your skin may be itchy
• You may pass less urine than usual.
• Dry socket (inflammation and pain after a tooth extraction)
• Increased sweating
• Low levels of potassium in blood test results.

Overdose Effects

Reporting of overdose with parecoxib has been associated with adverse reactions which have also been described with recommended doses of parecoxib. In case of overdose, patients should be managed by symptomatic and supportive care. Valdecoxib is not removed by haemodialysis. Diuresis or alkalisation of urine may not be useful due to high protein binding of valdecoxib.

Parecoxib has been studied in dental, orthopaedic, gynaecologic (principally hysterectomy) and coronary artery bypass graft surgery. There is limited experience in other types of surgery, for example gastrointestinal or urological surgery. Modes of administration other than IV or IM (e.g. intra-articular, intrathecal) have not been studied and should not be used. Because of the possibility for increaed adverse reactions at higher doses of parecoxib, other COX-2 inhibitors and NSAIDs, patients treated with parecoxib should be reviewed following dose increase and, in the absence of an increase in efficacy, other therapeutic options should be considered. There is limited clinical experience with Parecoxib treatment beyond three days. If, during treatment, patients deteriorate in any of the organ system functions described below, appropriate measures should be taken and discontinuation of parecoxib therapy should be considered.

Pregnancy & Lactation

Parecoxib is suspected to cause serious birth defects when administered during the last trimester of pregnancy because as with other medicinal products known to inhibit prostaglandin, it may cause premature closure of the ductus arteriosus or uterine inertia. NSAID use during the second or third trimester of pregnancy may cause foetal renal dysfunction which may result in reduction of amniotic fluid volume or oligohydramnios in severe cases. Such effects may occur shortly after treatment initiation 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 following caesarean section resulted in the transfer of a relatively small amount of parecoxib and its active metabolite valdecoxib into human milk, and this resulted in 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.