ZIPSOR
Clinical safety rating: caution
Comprehensive clinical and safety monograph for ZIPSOR (ZIPSOR).
Celecoxib is a nonsteroidal anti-inflammatory drug (NSAID) that selectively inhibits cyclooxygenase-2 (COX-2), reducing prostaglandin synthesis involved in inflammation, pain, and fever. It has no significant inhibition of COX-1 at therapeutic doses.
| Metabolism | Celecoxib is metabolized primarily by cytochrome P450 (CYP) 2C9 in the liver to inactive metabolites (hydroxycelecoxib and carboxycelecoxib). Minor metabolism via CYP3A4. |
| Excretion | Renal: ~60% unchanged; biliary/fecal: ~30% as metabolites; remainder as glucuronide conjugates |
| Half-life | 2-4 hours (terminal); clinical context: short half-life necessitates frequent dosing for sustained relief; prolonged in hepatic impairment |
| Protein binding | >99% bound to albumin |
| Volume of Distribution | 0.1-0.2 L/kg; low Vd indicates limited tissue distribution, primarily in plasma and extracellular fluid |
| Bioavailability | Oral: ~80-100% (immediate-release); rectal: ~70-90%; intramuscular: ~100% |
| Onset of Action | Oral (immediate-release): ~30 minutes; peak effect: 1-2 hours |
| Duration of Action | 4-6 hours (immediate-release); clinical note: duration correlates with analgesic effect; extended-release formulations provide up to 12-24 hours |
50 mg orally three times daily
| Dosage form | CAPSULE |
| Renal impairment | eGFR 30-59 mL/min: 25 mg three times daily; eGFR <30 mL/min: not recommended |
| Liver impairment | Child-Pugh class A: no adjustment; Child-Pugh class B: 25 mg three times daily; Child-Pugh class C: not recommended |
| Pediatric use | Not established; contraindicated in children less than 2 years of age |
| Geriatric use | No specific adjustment; use lowest effective dose; consider increased sensitivity to adverse effects |
| 1st trimester | Consult provider |
| 2nd trimester | Consult provider |
| 3rd trimester | Consult provider |
Clinical note
Comprehensive clinical and safety monograph for ZIPSOR (ZIPSOR).
| Breastfeeding | Limited data; diclofenac is excreted into breast milk in low levels (M/P ratio approximately 0.04). Breastfeeding is considered acceptable with caution, especially in infants with thrombocytopenia or bleeding disorders. Avoid use in nursing mothers with infants under 1 month or with renal impairment. |
| Teratogenic Risk | ZIPSOR (diclofenac potassium) is classified as FDA Pregnancy Category C prior to 30 weeks gestation and Category D starting at 30 weeks. First trimester: Risk of spontaneous abortion and congenital malformations (cardiac, orofacial clefts) based on epidemiological studies. Second trimester: Possible oligohydramnios and fetal renal dysfunction. Third trimester: Premature closure of ductus arteriosus, oligohydramnios, necrotizing enterocolitis, intracranial hemorrhage, and renal impairment. |
■ FDA Black Box Warning
Cardiovascular risk: NSAIDs increase the risk of serious cardiovascular thrombotic events, myocardial infarction, and stroke, which can be fatal. This risk may increase with duration of use and in patients with cardiovascular risk factors. ZIPSOR is contraindicated for the treatment of perioperative pain in coronary artery bypass graft (CABG) surgery.
| Serious Effects |
["Hypersensitivity to celecoxib or any component of the formulation","History of asthma, urticaria, or allergic-type reactions after taking aspirin or other NSAIDs","Coronary artery bypass graft (CABG) surgery","Advanced renal disease","Known sulfonamide hypersensitivity (cross-reactivity possible)"]
| Precautions | ["Cardiovascular thrombotic events: Use lowest effective dose for shortest duration.","Gastrointestinal effects: Risk of serious GI adverse events including bleeding, ulceration, and perforation.","Hypertension: NSAIDs can lead to new-onset hypertension or worsening of pre-existing hypertension.","Heart failure: Fluid retention and edema may occur.","Renal effects: Monitor renal function in patients with pre-existing renal disease, heart failure, or on diuretics.","Anaphylactoid reactions: Reported in patients with aspirin sensitivity.","Serious skin reactions: Including exfoliative dermatitis, Stevens-Johnson syndrome, and toxic epidermal necrolysis.","Pregnancy: Avoid use during late pregnancy (third trimester) due to risk of premature closure of ductus arteriosus.","Hematologic effects: May prolong bleeding time; monitor for signs of bleeding."] |
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| Fetal Monitoring | Monitor fetal ultrasound for oligohydramnios and ductus arteriosus patency after 30 weeks gestation. Evaluate maternal renal function, bleeding time, and blood pressure routinely. Assess for signs of fetal distress and growth restriction. |
| Fertility Effects | Diclofenac may impair female fertility by inhibiting prostaglandin synthesis, potentially leading to luteinized unruptured follicle syndrome and reversible delayed ovulation. Effects are reversible upon discontinuation. Male fertility impact is unclear. |