COX-2 Selective NSAID (Parenteral) Pregnancy: Contraindicated in the third trimester and during breast-feeding. No adequate data in pregnancy; should not be given during the first and second trimester unless clearly necessary, at the lowest dose and shortest duration. From week 20 onward may cause oligohydramnios from foetal renal dysfunction and ductus arteriosus constriction - consider antenatal monitoring and discontinue if either is found. Not recommended in women attempting to conceive.

Parecoxib

Brand names: Dynastat

Parecoxib is a parenteral selective COX-2 inhibitor (a prodrug of valdecoxib) used for short-term management of postoperative pain.

Auto-extracted from the source labelling — not yet independently clinician-verified. These values were distilled from the UK SPC (or the US label where noted) but have not had a clinician sign-off. Confirm against the current SmPC before prescribing.

Adult dose

Dose: 40 mg initially, followed by 20 mg or 40 mg as required

Route: Intravenous (IV) or intramuscular (IM). 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.

Frequency: Initial 40 mg, then 20 mg or 40 mg every 6 to 12 hours as required

Max: 80 mg/day (not to exceed). Reduce the maximum daily dose to 40 mg in elderly patients weighing less than 50 kg and in moderate hepatic impairment (Child-Pugh 7-9).

Verbatim from the SPC (Dynastat 40mg Powder and Solvent for Solution for Injection, section 4.2): '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 possible duration and the lowest effective daily dose should be used; there is limited clinical experience beyond three days. Opioid analgesics can be used concurrently, with parecoxib dosed as above. Elderly: no dose adjustment generally necessary in patients 65 years and over, but in elderly patients weighing less than 50 kg initiate at half the usual recommended dose and reduce the maximum daily dose to 40 mg. Hepatic impairment: no adjustment in mild impairment (Child-Pugh 5-6); introduce with caution at half the usual recommended dose in moderate impairment (Child-Pugh 7-9) with maximum daily dose 40 mg; contraindicated in severe hepatic impairment (Child-Pugh 10 or more). Paediatric population: safety and efficacy in children under 18 years have not been established, no data available, therefore not recommended. Administration: must not be mixed with any other medicinal product during reconstitution or injection (precipitation may occur); flush shared IV lines before and after with a compatible solution; after reconstitution may only be injected IV or IM or into lines delivering sodium chloride 0.9%, glucose 5%, sodium chloride 0.45% with glucose 5%, or Ringer-Lactate. NOTE: the fetched SPC sections 4.6 and 4.8 were truncated at the source-fetch limit; section 4.5 (interactions) was not fetched.

Dose adjustments

Renal

In severe renal impairment (creatinine clearance below 30 ml/min) or patients who may be predisposed to fluid retention, initiate at the lowest recommended dose (20 mg) and monitor kidney function closely. No dose adjustment is necessary in mild to moderate renal impairment (creatinine clearance 30-80 ml/min).

Dose auto-extracted from UK Summary of Product Characteristics (SPC) via the eMC — not yet clinician-verified. Always confirm against the product SmPC and your local formulary before prescribing.

Contraindications

Hypersensitivity to the active substance or to any of the excipients
History of previous serious allergic drug reaction of any type, especially cutaneous reactions such as Stevens-Johnson syndrome, DRESS, toxic epidermal necrolysis, erythema multiforme, or known hypersensitivity to sulfonamides
Active peptic ulceration or gastrointestinal bleeding
Patients who have experienced bronchospasm, acute rhinitis, nasal polyps, angioneurotic oedema, urticaria or other allergic-type reactions after acetylsalicylic acid or NSAIDs including COX-2 inhibitors
Third trimester of pregnancy and breast-feeding
Severe hepatic impairment (serum albumin below 25 g/l or Child-Pugh score 10 or more)
Inflammatory bowel disease
Congestive heart failure (NYHA II-IV)
Treatment of post-operative pain following coronary artery bypass graft (CABG) surgery
Established ischaemic heart disease, peripheral arterial disease and/or cerebrovascular disease

Side effects

Nausea (very common); vomiting, abdominal pain, constipation, dyspepsia, flatulence (common); gastroduodenal ulceration, GORD, dry mouth (uncommon)
Cardiovascular: hypertension and hypotension (common); myocardial infarction, bradycardia (uncommon); circulatory collapse, congestive heart failure, tachycardia (rare)
Post-operative anaemia (common); thrombocytopenia (uncommon); hypokalaemia (common)
Nervous system: hypoaesthesia, dizziness (common); agitation, insomnia (common); cerebrovascular disorder (rare)
Skin/hypersensitivity: pruritus, hyperhidrosis (common); ecchymosis, rash, urticaria (uncommon); Stevens-Johnson syndrome, erythema multiforme, exfoliative dermatitis (rare); anaphylaxis and angioedema (not known)
Renal: oliguria (uncommon), acute renal failure (rare), blood creatinine increased (common)
Following CABG surgery: higher risk of cardiovascular/thromboembolic events, deep surgical infections and sternal wound healing complications

Clinical monograph

How it works

After conversion to valdecoxib it selectively inhibits cyclo-oxygenase-2, reducing prostaglandin-mediated inflammation and pain with relatively less effect on platelet function.

Prescribing in practice

It is contraindicated after coronary artery bypass graft surgery owing to an increased risk of serious cardiovascular and thrombotic events.
Avoid in serious cardiovascular disease, active gastrointestinal bleeding and significant renal impairment, and use the shortest effective duration.
Serious skin reactions and hypersensitivity, including in patients with aspirin- or NSAID-sensitive asthma, have been reported.

Monitoring

Monitor renal function, blood pressure and for gastrointestinal or hypersensitivity reactions, particularly in at-risk patients.

Counselling the patient

This is a short-course injection for pain after surgery.
Report any rash, swelling or breathing difficulty immediately.

Evidence & guidelines

Selective COX-2 inhibitors carry a known cardiovascular safety signal, with parecoxib specifically contraindicated post-CABG per MHRA and SPC warnings.

Reference: NICE Analgesics Review; Dynastat SPC; Drug verified in RxNorm (NLM); confirm dosing against the manufacturer SPC (eMC). Verify against your local formulary and current prescribing references before prescribing. The structured dose values shown have been reviewed by a clinician. Monograph status: clinician-reviewed (2026-07-04).

Curated clinical cross-links plus same-class fallbacks.

Pathways