Dynastat (Parecoxib)
Injectable COX-2 inhibitor for short-term postoperative pain relief
Quick Facts About Dynastat
Key Takeaways About Dynastat
- Injectable pain relief after surgery: Dynastat is a COX-2 inhibitor given by IV or IM injection for short-term postoperative pain management in adults only
- Maximum 80 mg per day: The usual starting dose is 40 mg, with additional doses of 20–40 mg every 6–12 hours, not exceeding 80 mg daily
- Not for long-term use: Treatment should be limited to the shortest duration necessary, with limited clinical experience beyond 3 days
- Cardiovascular and GI risks: Do not use in patients with established heart disease, history of stroke, peptic ulcers, or gastrointestinal bleeding
- Many drug interactions: Interacts with warfarin, ACE inhibitors, lithium, methotrexate, fluconazole, and other common medications – always inform your healthcare provider of all medicines you take
What Is Dynastat and What Is It Used For?
Dynastat (parecoxib) is an injectable selective COX-2 inhibitor used for the short-term management of postoperative pain in adults. It belongs to a group of medicines called coxibs that reduce pain and inflammation by decreasing the production of prostaglandins in the body.
Dynastat contains the active substance parecoxib, which is a prodrug that is rapidly converted to valdecoxib in the body after injection. Valdecoxib is the pharmacologically active compound that selectively inhibits the enzyme cyclooxygenase-2 (COX-2). This selectivity is important because COX-2 is primarily responsible for producing prostaglandins at sites of tissue injury and inflammation, while COX-1 produces prostaglandins that protect the stomach lining and support platelet function.
Pain and swelling following surgery are caused by substances in the body called prostaglandins. By selectively reducing the production of these inflammatory prostaglandins through COX-2 inhibition, Dynastat provides effective pain relief while theoretically preserving some of the protective functions of COX-1-derived prostaglandins in the gastrointestinal tract. However, as with all COX-2 inhibitors, the cardiovascular safety profile requires careful patient selection.
Dynastat is exclusively administered in clinical settings – hospitals, surgical centres, and recovery units – by trained healthcare professionals. It is given as an intravenous (IV) or intramuscular (IM) injection, making it suitable for patients who cannot take oral medications after surgery, such as those who have undergone gastrointestinal procedures or who are experiencing nausea and vomiting.
Clinical trials have demonstrated that Dynastat 40 mg provides analgesic efficacy comparable to ketorolac 30 mg for postoperative pain. The onset of analgesia typically occurs within 7–13 minutes after intravenous administration and within 30–45 minutes after intramuscular injection, with peak effects reached at approximately 2 hours. This rapid onset makes it particularly useful in the immediate postoperative period when prompt pain control is essential.
Dynastat is intended only for short-term postoperative use. There is limited clinical experience with treatment beyond 3 days. Because cardiovascular risk associated with COX-2 inhibitors may increase with dose and duration of treatment, the shortest possible treatment duration should be used at the lowest effective daily dose.
What Should You Know Before Taking Dynastat?
Dynastat must not be used in patients with established cardiovascular disease, active gastrointestinal ulcers or bleeding, severe liver disease, inflammatory bowel disease, or known allergy to parecoxib, sulfonamides, aspirin, or other NSAIDs. It is also contraindicated for coronary artery bypass graft (CABG) surgery.
Contraindications
Several important conditions absolutely prevent the use of Dynastat. Your healthcare provider will assess these before administering the medication. You should not receive Dynastat if any of the following apply:
- Allergy to parecoxib or any other ingredient in the formulation
- History of severe allergic reaction (particularly severe skin reactions) to any medicine
- Allergy to sulfonamides (including certain antibiotics used to treat infections)
- Current peptic ulcer, intestinal ulcer, or bleeding in the stomach or intestines
- History of allergic reactions to aspirin, NSAIDs, or COX-2 inhibitors, including bronchospasm, severe nasal congestion, skin rash, or angioedema
- Pregnancy beyond the 6th month
- Breastfeeding
- Severe liver disease
- Inflammatory bowel disease (ulcerative colitis or Crohn's disease)
- Heart failure
- Undergoing heart surgery or arterial bypass, including coronary artery bypass grafting (CABG)
- Established cardiovascular or cerebrovascular disease, including previous heart attack, stroke, transient ischaemic attack (TIA), or narrowing of blood vessels to the heart or brain
- Peripheral arterial disease (problems with blood circulation in the limbs)
Potentially life-threatening skin rashes, including Stevens-Johnson syndrome and toxic epidermal necrolysis, have been reported with Dynastat. Treatment must be stopped at the first appearance of skin rash, blistering, peeling skin, mucosal lesions, or any sign of hypersensitivity. The frequency of these reactions appears to be higher for valdecoxib (the active metabolite of parecoxib) compared to other COX-2 inhibitors. If you develop any rash or other skin or mucosal symptoms, inform your healthcare provider immediately.
Warnings and Precautions
Even if you do not have a clear contraindication, several conditions require special caution. Tell your doctor or nurse before receiving Dynastat if you have:
- A history of stomach or intestinal ulcers, bleeding, or perforation
- Any previous skin reaction (rash, hives, blisters, red streaks) to any medicine
- Current use of aspirin or other NSAIDs (e.g., ibuprofen)
- Smoking or alcohol use (increases gastrointestinal risk)
- Diabetes mellitus
- Angina, blood clots, high blood pressure, or elevated cholesterol
- Use of antiplatelet medications
- Fluid retention (oedema)
- Liver or kidney disease
- Dehydration (from diarrhoea, vomiting, or inability to drink fluids)
- An infection (Dynastat can mask fever, which is a sign of infection)
- Use of anticoagulants (warfarin or newer oral anticoagulants such as apixaban, dabigatran, rivaroxaban)
- Use of corticosteroids (e.g., prednisolone)
- Use of SSRIs (e.g., sertraline) for depression
Dynastat can raise blood pressure or worsen existing hypertension, which may lead to an increase in cardiovascular side effects. Your doctor may wish to monitor your blood pressure during treatment. Additionally, Dynastat is not recommended for children and adolescents under 18 years of age.
Pregnancy and Breastfeeding
Dynastat must not be used during the last 3 months (third trimester) of pregnancy because it can cause serious harm to the unborn baby and complications during delivery. Specifically, it may cause kidney and heart problems in the foetus, affect the tendency to bleed in both mother and baby, and cause labour to be delayed or prolonged.
During the first 6 months of pregnancy, Dynastat should only be used if absolutely necessary and recommended by the prescribing physician. If treatment is needed during this period or while trying to conceive, the lowest possible dose should be used for the shortest possible duration. If Dynastat is used for more than a few days from week 20 of pregnancy onwards, it may cause kidney problems in the unborn baby leading to low amniotic fluid (oligohydramnios) or constriction of the ductus arteriosus in the baby's heart.
Breastfeeding mothers should not receive Dynastat, as a small amount of the drug passes into breast milk. NSAIDs, including Dynastat, may also impair fertility. Women who are planning to become pregnant or who are having difficulty conceiving should discuss this with their doctor.
Dynastat contains less than 1 mmol (23 mg) sodium per mL, meaning it is essentially sodium-free. This is relevant for patients on a sodium-restricted diet.
How Does Dynastat Interact with Other Drugs?
Dynastat interacts with several commonly used medications including anticoagulants (warfarin, apixaban), blood pressure medications, lithium, methotrexate, and fluconazole. Always inform your healthcare provider about all medications you are taking, as dose adjustments may be necessary.
Drug interactions are a critical consideration with Dynastat, particularly in the perioperative setting where patients may be receiving multiple medications simultaneously. Some interactions can increase the risk of adverse effects, while others may alter the effectiveness of either Dynastat or the interacting medication. Your healthcare team needs to be aware of all medications you are currently taking.
Major Interactions
| Interacting Drug | Effect | Clinical Significance |
|---|---|---|
| Warfarin and similar anticoagulants (including apixaban, dabigatran, rivaroxaban) | Increased risk of bleeding; parecoxib may increase INR values | Monitor coagulation parameters closely, especially in the first few days of combined use |
| ACE inhibitors, ARBs, beta-blockers, diuretics | Reduced antihypertensive effect; increased risk of renal impairment | Monitor blood pressure and renal function; ensure adequate hydration |
| Fluconazole | Doubles plasma levels of valdecoxib (active metabolite) via CYP2C9 inhibition | Dose of Dynastat should be halved; start with 20 mg, max 40 mg/day |
| Lithium | Increased lithium plasma levels due to reduced renal clearance | Monitor lithium levels during and after co-administration |
| Methotrexate | Increased methotrexate plasma concentrations; increased toxicity risk | Monitor for methotrexate-related side effects; check blood counts |
| Ciclosporin or tacrolimus | Increased risk of nephrotoxicity (kidney damage) | Monitor renal function closely during combined use |
Other Notable Interactions
| Interacting Drug | Effect | Action Required |
|---|---|---|
| Aspirin / other NSAIDs | Increased GI bleeding risk; no additional cardiovascular benefit from low-dose aspirin | Avoid combination if possible; use lowest doses |
| Rifampicin | Reduced plasma levels of valdecoxib via CYP3A4 induction | May require dose adjustment; monitor pain control |
| Phenytoin / carbamazepine | May alter plasma levels of both drugs | Monitor anticonvulsant levels |
| Diazepam | Reduced clearance of diazepam | Monitor for increased sedation |
| Omeprazole | No clinically significant interaction | No dose adjustment needed |
| Antiarrhythmics | Potential for altered drug metabolism | Monitor cardiac rhythm and drug levels |
It is especially important to inform your anaesthetist and surgical team about all medications you are taking before surgery. This includes prescription medicines, over-the-counter drugs, herbal supplements, and vitamins. Some interactions may not become apparent until the perioperative period when multiple drugs are administered simultaneously.
What Is the Correct Dosage of Dynastat?
The recommended starting dose of Dynastat is 40 mg given intravenously or intramuscularly, followed by 20 mg or 40 mg every 6 to 12 hours as needed, up to a maximum of 80 mg per day. Treatment should be limited to the shortest duration necessary.
Dynastat is always administered by a healthcare professional. The powder must be reconstituted with an appropriate solvent before injection. Intravenous bolus injection can be given rapidly and directly into a vein or through an existing IV line. Intramuscular injection should be given slowly and deeply into the muscle.
Adults
Standard Adult Dosing
- Initial dose: 40 mg IV or IM
- Subsequent doses: 20 mg or 40 mg every 6–12 hours as needed
- Maximum daily dose: 80 mg per 24 hours
- Duration: Shortest possible; limited clinical experience beyond 3 days
- Route: Intravenous (rapid bolus) or intramuscular (slow, deep injection)
Special Populations Requiring Dose Adjustment
| Patient Group | Recommended Dose | Notes |
|---|---|---|
| Hepatic impairment (mild) | No adjustment needed | Use with caution; monitor liver function |
| Hepatic impairment (moderate) | Reduce dose by half | Start with 20 mg; max 40 mg/day |
| Hepatic impairment (severe) | Contraindicated | Do not use |
| Severe renal impairment | Reduce dose | Use with caution; monitor renal function closely |
| Elderly (>65 years, <50 kg) | Reduce dose | Start with lower dose; increased risk of adverse effects |
| Patients taking fluconazole | Reduce dose by half | Fluconazole doubles valdecoxib levels; max 40 mg/day |
Children
Dynastat is not recommended for use in children and adolescents under 18 years of age. Safety and efficacy have not been established in the paediatric population. Alternative analgesic strategies should be used for postoperative pain management in younger patients.
Use with Opioid Analgesics
When Dynastat is used in combination with opioid analgesics such as morphine for multimodal pain management, the dose of Dynastat remains the same as described above. The combination of a COX-2 inhibitor with opioids is a well-established strategy in perioperative analgesia that may allow for reduced opioid consumption, potentially reducing opioid-related side effects such as respiratory depression, nausea, and sedation.
Overdose
If too much Dynastat is administered, you may experience side effects that have been reported at recommended doses, but potentially with greater severity. In the event of an overdose, treatment is supportive and symptomatic. Parecoxib is not removed by haemodialysis. If you suspect an overdose, inform your healthcare provider immediately.
What Are the Side Effects of Dynastat?
The most common side effect of Dynastat is nausea (affecting more than 1 in 10 patients). Other common side effects include changes in blood pressure, back pain, swelling of extremities, numbness, vomiting, constipation, dizziness, and insomnia. Serious but less common side effects include heart attack, stroke, and severe skin reactions.
Like all medicines, Dynastat can cause side effects, although not everyone experiences them. The frequency and severity of side effects vary between individuals. Many side effects resolve once treatment is stopped. It is important to be aware of the signs of serious side effects that require immediate medical attention.
Skin rash or sores anywhere on the body (skin, mouth, eyes, face, lips, tongue), or signs of an allergic reaction including swelling of the face, lips, or tongue causing wheezing, breathing difficulties, or difficulty swallowing. Skin reactions can occur at any time but are most common during the first month of treatment. Also seek immediate help for signs of gastrointestinal bleeding (black or bloody stools, vomiting blood) or jaundice (yellowing of skin or eyes).
Very Common
May affect more than 1 in 10 patients
- Nausea
Common
May affect up to 1 in 10 patients
- Blood pressure changes (increase or decrease)
- Back pain
- Swelling of ankles, legs, and feet (fluid retention/oedema)
- Numbness or loss of sensation (paraesthesia)
- Vomiting, stomach pain, indigestion, constipation, flatulence
- Abnormal kidney function test results
- Anxiety and insomnia
- Dizziness
- Anaemia (reduced red blood cells) causing tiredness and breathlessness
- Sore throat or difficulty breathing (dyspnoea)
- Itching (pruritus)
- Decreased urine output
- Post-extraction alveolitis (inflammation after tooth extraction)
- Increased sweating (hyperhidrosis)
- Low potassium levels in the blood (hypokalaemia)
Uncommon
May affect up to 1 in 100 patients
- Heart attack (myocardial infarction)
- Stroke or transient ischaemic attack (TIA/mini-stroke)
- Blood clots in the lungs (pulmonary embolism)
- Worsening of existing high blood pressure
- Peptic ulcer, acid reflux
- Slow heart rate (bradycardia)
- Low blood pressure on standing (postural hypotension)
- Abnormal liver function test results
- Easy bruising due to low platelet count (thrombocytopenia)
- Wound infection or abnormal wound discharge
- Skin discolouration or bruising
- Surgical wound healing complications
- High blood sugar levels (hyperglycaemia)
- Injection site pain or reaction
- Rash or worsening itchy rash (urticaria)
- Loss of appetite (anorexia)
- Joint pain (arthralgia)
- Elevated creatine kinase levels
- Dry mouth, muscle weakness, ear pain
Rare
May affect up to 1 in 1,000 patients
- Acute kidney failure
- Hepatitis (liver inflammation)
- Oesophagitis (inflammation of the oesophagus)
- Pancreatitis (inflammation of the pancreas, causing abdominal pain)
Frequency Not Known
Cannot be estimated from available data
- Circulatory collapse due to very low blood pressure
- Heart failure
- Kidney failure
- Palpitations or irregular heartbeat (arrhythmia)
- Shortness of breath
- Skin swelling, blistering, or peeling (including Stevens-Johnson syndrome)
If you notice any side effects not listed here, or if any side effect becomes severe, tell your doctor or nurse. You can also report suspected side effects to your national medicines regulatory authority to help monitor the ongoing benefit-risk balance of the medicine.
How Should You Store Dynastat?
Store Dynastat out of the sight and reach of children. No special storage conditions are required for the unopened product. Once reconstituted, the solution should be used immediately or within 24 hours at 25°C under controlled aseptic conditions.
The unreconstituted powder for injection does not require any special storage conditions. It should be kept in the original packaging and should not be used after the expiry date printed on the carton and label (the expiry date refers to the last day of the stated month).
Once the powder has been reconstituted with a suitable diluent, it is recommended to use the solution as soon as possible. Chemical and physical stability of the reconstituted solution has been demonstrated for up to 24 hours at 25°C. However, due to the significant risk of microbiological contamination with injectable products, the reconstituted solution should be used immediately unless preparation has been carried out under controlled and validated aseptic conditions. If these requirements are not met, in-use storage times and conditions are the user's responsibility and should not exceed 12 hours at 25°C.
The injection solution should be a clear, colourless liquid. If there are particles in the solution, or if the powder or solution is discoloured, it must not be used. Any unused solution should be discarded in accordance with local waste disposal requirements.
What Does Dynastat Contain?
Each Dynastat vial contains 40 mg parecoxib (as 42.36 mg parecoxib sodium). When reconstituted with 2 mL of diluent, the concentration is 20 mg/mL. Excipients include disodium hydrogen phosphate, phosphoric acid and/or sodium hydroxide (for pH adjustment).
Active Ingredient
The active substance is parecoxib, supplied as parecoxib sodium. Each 5 mL glass vial contains 40 mg parecoxib in the form of 42.36 mg parecoxib sodium. When reconstituted with the supplied 2 mL of diluent, the resulting solution has a concentration of 20 mg/mL parecoxib. When reconstituted with 0.9% sodium chloride solution, Dynastat contains approximately 0.44 mEq sodium per vial.
Other Ingredients
Powder: Disodium hydrogen phosphate, phosphoric acid and/or sodium hydroxide (for pH adjustment).
Solvent: Sodium chloride, hydrochloric acid or sodium hydroxide (for pH adjustment), water for injections.
Appearance and Packaging
Dynastat is supplied as a white to off-white powder in a 5 mL colourless glass vial with a stopper and purple flip-off cap over an aluminium seal. The solvent is provided in a 2 mL colourless glass ampoule. The powder is reconstituted to form a clear, colourless solution before injection.
Reconstitution
Dynastat may only be reconstituted with the following compatible diluents:
- 0.9% sodium chloride solution for injection/infusion
- 5% glucose solution for infusion
- 0.45% sodium chloride with 5% glucose injection/infusion solution
Do not reconstitute with Ringer's lactate solution or Ringer's lactate with 5% glucose, as this causes precipitation of parecoxib. Sterile water for injections is also not recommended because the resulting solution would not be isotonic. Dynastat must not be mixed with any other medication during preparation or injection.
Frequently Asked Questions About Dynastat
Dynastat (parecoxib) is used exclusively for the short-term treatment of postoperative pain in adults. It is a COX-2 inhibitor given by injection (intravenous or intramuscular) in hospital or clinical settings. It is administered by healthcare professionals when patients cannot take oral pain medication after surgery, or when rapid onset of pain relief is needed. It is not intended for long-term pain management or for conditions such as arthritis.
When given intravenously, Dynastat typically begins to provide pain relief within 7 to 13 minutes. When administered intramuscularly, the onset is slower, usually within 30 to 45 minutes. Peak analgesic effect is generally reached approximately 2 hours after injection, regardless of the route of administration. The duration of pain relief varies but typically lasts 6 to 12 hours.
If you feel dizzy or tired after receiving a Dynastat injection, you should not drive or operate machinery until you feel better. Since Dynastat is typically given in hospital settings after surgery, driving is usually not an immediate concern. However, you should ensure you have fully recovered from the effects of both the surgery and any medications before driving. Discuss with your healthcare provider when it is safe to resume driving.
As a selective COX-2 inhibitor, Dynastat was designed to have fewer gastrointestinal side effects compared to non-selective NSAIDs like ibuprofen or diclofenac. By selectively inhibiting COX-2 while sparing COX-1 (which has protective effects on the stomach lining), the risk of peptic ulcers and gastrointestinal bleeding may be lower. However, gastrointestinal complications can still occur, and Dynastat is still contraindicated in patients with active peptic ulcers or gastrointestinal bleeding. The GI advantage is most relevant for short-term postoperative use.
Before receiving Dynastat, tell your doctor about all your medical conditions, especially: heart disease, high blood pressure, or history of stroke; stomach ulcers or gastrointestinal bleeding; liver or kidney disease; asthma or allergies to aspirin or NSAIDs; diabetes; bleeding disorders; any current infections; and whether you are pregnant, breastfeeding, or planning to become pregnant. Also provide a complete list of all medications you are taking, including over-the-counter drugs and supplements, as Dynastat interacts with many common medicines.
Dynastat is intended for short-term use only, and there is limited clinical experience with treatment beyond 3 days. The cardiovascular risk associated with COX-2 inhibitors may increase with longer treatment durations, so the shortest possible treatment period should be used. Your healthcare team will typically transition you to oral pain medications as soon as you are able to take them. The exact duration of treatment depends on your individual clinical situation and the type of surgery performed.
References
- European Medicines Agency (EMA). Dynastat – Summary of Product Characteristics. Last updated 2025. Available at: EMA – Dynastat EPAR.
- Pfizer Inc. Dynastat (parecoxib sodium) Prescribing Information. Pfizer Europe MA EEIG, Brussels, Belgium. 2025.
- Lloyd R, Derry S, Moore RA, McQuay HJ. Intravenous or intramuscular parecoxib for acute postoperative pain in adults. Cochrane Database of Systematic Reviews. 2009;(2):CD004771. doi:10.1002/14651858.CD004771.pub4.
- Schug SA, Parsons B, Li C, Xia F. The safety profile of parecoxib for the treatment of postoperative pain: a pooled analysis of 28 randomized, double-blind, placebo-controlled clinical trials. Journal of Pain Research. 2017;10:1489–1500.
- World Health Organization (WHO). WHO Model List of Essential Medicines – 23rd List (2023). Geneva: World Health Organization; 2023.
- British National Formulary (BNF). Parecoxib. National Institute for Health and Care Excellence (NICE). Available at: bnf.nice.org.uk.
- Nussmeier NA, Whelton AA, Brown MT, et al. Complications of the COX-2 inhibitors parecoxib and valdecoxib after cardiac surgery. New England Journal of Medicine. 2005;352(11):1081–1091.
- Ott E, Nussmeier NA, Duke PC, et al. Efficacy and safety of the cyclooxygenase 2 inhibitors parecoxib and valdecoxib in patients undergoing coronary artery bypass surgery. Journal of Thoracic and Cardiovascular Surgery. 2003;125(6):1481–1492.
About Our Medical Editorial Team
This article has been written and reviewed by the iMedic Medical Editorial Team, consisting of licensed physicians with expertise in pharmacology, pain medicine, and perioperative care. Our team follows international evidence-based guidelines from the WHO, EMA, and BNF to ensure the highest accuracy and reliability.
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