Dynastat (Parecoxib)
Parenteral COX 2 inhibitor for postoperative pain therapy
Dynastat is the brand name of the active substance parecoxib, a parenterally administered prodrug of the selective COX 2 inhibitor valdecoxib. Pfizer launched the compound in Europe in 2002, and in Germany it is used for short term postoperative pain therapy in adults. Dynastat is the only parenteral coxib on the European market and therefore occupies a special niche in the immediate postoperative phase.
Use is limited to intravenous or intramuscular administration and takes place exclusively in inpatient or monitored outpatient settings. After reconstitution parecoxib is rapidly converted in the liver by hydrolysis to valdecoxib, which exerts the actual analgesic effect. The typical indication is short term pain relief over 1 to 3 postoperative days, often as part of a multimodal analgesia alongside opioids, paracetamol and regional analgesia.
Mechanism of Action
Parecoxib is a prodrug without analgesic activity of its own. After intravenous or intramuscular administration it is converted to valdecoxib within about 20 minutes by hepatic carboxylesterases. Valdecoxib is a selective inhibitor of cyclooxygenase 2 (COX 2) with much lower affinity for COX 1. Inhibition of COX 2 reduces inflammation driven prostaglandin formation at tissue lesions, producing analgesic, antipyretic and anti inflammatory effects.
Selectivity for COX 2 largely preserves COX 1 dependent thromboxane A2 and mucosal protection. The consequence is a reduced risk of gastrointestinal ulcers and bleeding compared with non selective NSAIDs, together with less impairment of platelet function. The cardiovascular risk, however, is elevated because COX 1 dependent prostacyclin, which is vasoprotective, is reduced while COX 2 mediated platelet effects remain unaffected.
The half life of valdecoxib is about 8 hours, and onset of action after intravenous administration occurs within 7 to 13 minutes. Metabolism is predominantly hepatic via CYP3A4 and CYP2C9, and elimination is mostly renal as metabolites.
Indications
- Short term treatment of postoperative pain in adults, particularly after orthopaedic, abdominal, gynaecological and urological procedures
- Part of a multimodal analgesia with paracetamol, opioids and regional analgesia, for opioid sparing
- Patients with elevated gastrointestinal bleeding risk in the postoperative phase, in whom non selective NSAIDs are contraindicated
- Situations with inadequate oral intake (fasting, postoperative gastrointestinal atony)
Dynastat is not approved for chronic pain therapy, headache treatment or the therapy of inflammatory rheumatological disease. Use is strictly limited to the immediate postoperative phase and to selected situations.
Dosage and Administration
Standard dose: 40 mg as initial dose intravenously or intramuscularly, followed by 20 to 40 mg every 6 to 12 hours, maximum daily dose 80 mg. Treatment duration should be limited to 3 days, then switch to orally administered analgesics (NSAIDs, paracetamol).
Reconstitution uses sterile saline or glucose solution. The ready made solution is stable for 24 hours. Intravenous bolus administration as a 1 to 2 minute injection, intramuscular administration deep into the upper arm or gluteal muscle. Combination with other NSAIDs is not reasonable, whereas combination with opioids or paracetamol is additively effective.
Renal impairment: mild to moderate impairment low starting dose 20 mg, severe impairment contraindicated. Hepatic impairment: mild impairment no adjustment, moderate impairment 20 mg, severe impairment contraindicated. Elderly patients over 65 years: with body weight below 50 kg starting dose 20 mg.
Side Effects
Very common and common: nausea, vomiting, constipation, flatulence, dyspepsia, pharyngitis, alveolar osteitis (dry socket after tooth extraction), postoperative skin oedema, hypotension, bradycardia, headache, fever, injection site reaction.
Uncommon: elevated creatinine and urea values, hyperkalaemia, dizziness, insomnia, agitation, respiratory depression (especially in combination with opioids), hyperglycaemia, pruritus, increased sweating.
Rare and serious: cardiovascular events (myocardial infarction, stroke), severe skin reactions such as Stevens Johnson syndrome, toxic epidermal necrolysis, erythema multiforme, severe anaphylaxis, acute renal failure, severe hypertension, gastrointestinal bleeding or perforation, bronchospasm, angioedema, liver failure.
Special warning on cardiac risk: Because of the elevated risk of cardiovascular events, Dynastat is contraindicated in coronary artery disease, after bypass surgery, in peripheral arterial disease and in cerebrovascular disease. Valdecoxib, the active form, was withdrawn from the market worldwide in 2005; identical safety concerns apply to parecoxib, but the parenteral short term use remains approved under strict conditions.
Interactions
- Other NSAIDs, acetylsalicylic acid: additive bleeding risk, avoid combination
- Anticoagulants (warfarin, DOACs, heparins): elevated bleeding risk despite less platelet effect
- Antihypertensives (ACE inhibitors, ARBs, diuretics, beta blockers): attenuation of the effect, particularly problematic in volume depletion
- Lithium, methotrexate: elevated plasma levels due to reduced renal elimination
- CYP2C9 inhibitors (fluconazole, amiodarone): plasma levels of valdecoxib rise, consider dose adjustment
- CYP3A4 inducers (rifampicin, carbamazepine, phenytoin): accelerated degradation, attenuation of the effect
- Opioids: synergistic analgesia, opioid sparing of about 30 to 40 percent in studies
- Dextromethorphan: elevated plasma levels
Special Notes
Contraindications: known coronary artery disease, status after coronary artery bypass grafting, peripheral arterial disease, cerebrovascular disease, severe heart failure, active gastrointestinal bleeding or ulcer, chronic inflammatory bowel disease with active lesion, severe renal or hepatic impairment, third trimester of pregnancy, breastfeeding, children under 18 years, known severe skin reaction to sulfonamides, asthma with analgesic intolerance.
Postoperative monitoring: After Dynastat administration monitor blood pressure, heart rate, urine output and respiration. Watch particularly for respiratory depression when combined with opioids. Nephroprotective measures (fluid balance, electrolyte balance) are important because NSAIDs impair renal autoregulation.
Pregnancy: use in the first and second trimester only when clearly indicated, contraindicated in the third trimester because of the risk of premature closure of the ductus arteriosus and of fetal renal damage. Breastfeeding: passage into breast milk possible, breastfeeding under therapy not recommended.
Monitoring: renal retention values, electrolytes (potassium), blood count and coagulation before and during therapy. ECG before starting therapy in patients with cardiovascular risk.
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Frequently Asked Questions
What is the difference between Dynastat and classic NSAIDs?
Parecoxib selectively inhibits COX 2 and spares COX 1. This lowers the risk of gastrointestinal bleeding and platelet effects, which is an advantage in the perioperative setting. The cardiovascular risk, however, is elevated, which is why Dynastat is contraindicated in patients with pre existing cardiovascular disease. Treatment remains limited to a few days.
Why was valdecoxib withdrawn from the market but Dynastat was not?
Oral valdecoxib was withdrawn worldwide in 2005 because of rare but life threatening skin reactions such as Stevens Johnson syndrome and because of elevated cardiovascular risks. As a parenteral short term application, Dynastat retained its approval under strict conditions, because the short application window of a maximum of 3 days limits the risk and the perioperative benefit outweighs it in certain situations.
Does Dynastat spare opioids?
Yes. In studies Dynastat reduces postoperative opioid requirements by about 30 to 40 percent. This decreases typical opioid side effects such as nausea, constipation and respiratory depression. Multimodal analgesia with paracetamol, Dynastat, regional analgesia and demand adapted opioids is the current standard.
Who must not receive Dynastat?
Patients with coronary artery disease, after bypass surgery, with peripheral arterial disease, with cerebrovascular disease and with severe heart failure are excluded from therapy. The substance is also contraindicated in severe renal or hepatic impairment, in active ulcer bleeding and in the third trimester of pregnancy.
Sources
- EMA, Dynastat (Parecoxib) EPAR
- AWMF, S3 guideline on acute perioperative pain therapy
- Gelbe Liste, parecoxib active substance profile
- BfArM, Federal Institute for Drugs and Medical Devices
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