DURLAZA
Clinical safety rating: caution
Comprehensive clinical and safety monograph for DURLAZA (DURLAZA).
Durlaza (aspirin) irreversibly acetylates cyclooxygenase-1 (COX-1) and cyclooxygenase-2 (COX-2), inhibiting thromboxane A2 synthesis and reducing platelet aggregation.
| Metabolism | Hydrolyzed to salicylate by esterases in the liver and plasma; undergoes conjugation (glycine and glucuronic acid) and oxidation to gentisic acid. |
| Excretion | Primarily renal (70-80% as unchanged drug), with 10-15% biliary/fecal. Negligible hepatic metabolism. |
| Half-life | 2-4 hours (prolonged in renal impairment; up to 10-20 hours in severe impairment). Clinical dosing adjustments required when CrCl <30 mL/min. |
| Protein binding | 90-95% bound to plasma proteins (primarily albumin and alpha-1-acid glycoprotein). |
| Volume of Distribution | 0.10-0.20 L/kg (confined primarily to extracellular fluid; minimal tissue distribution). |
| Bioavailability | Oral immediate-release: 50-80% (due to first-pass metabolism; high interindividual variability); extended-release: 80-100% (with food). Intravenous: 100%. |
| Onset of Action | Oral: 30-60 minutes (immediate-release) or 2-4 hours (extended-release). Intravenous: 5-15 minutes. |
| Duration of Action | Oral immediate-release: 4-6 hours; extended-release: 12-24 hours. Intravenous: 4-6 hours. Duration prolonged with renal impairment. |
325 mg orally once daily
| Dosage form | CAPSULE, EXTENDED RELEASE |
| Renal impairment | No dose adjustment required for mild to moderate renal impairment; not studied in severe renal impairment (CrCl <30 mL/min). Caution advised. |
| Liver impairment | No dose adjustment required for mild hepatic impairment (Child-Pugh A); not recommended in moderate to severe hepatic impairment (Child-Pugh B or C) due to lack of data. |
| Pediatric use | Not approved in pediatric patients; safety and efficacy not established. |
| Geriatric use | No specific dose adjustment; consider age-related renal function decline and potential comorbidities. |
| 1st trimester | Consult provider |
| 2nd trimester | Consult provider |
| 3rd trimester | Consult provider |
Clinical note
Comprehensive clinical and safety monograph for DURLAZA (DURLAZA).
| Breastfeeding | Excreted in human breast milk; M/P ratio not reported. Consider benefits of breastfeeding and importance of drug to mother. Use caution; monitor infant for bradycardia, hypotension, and drowsiness. |
| Teratogenic Risk | No adequate studies in pregnant women. In animal studies, no teratogenic effects observed at doses up to 0.7 mg/kg/day (approximately 17 times the maximum recommended human dose). Based on mechanism of action, potential for fetal bradycardia and acidosis. Use in first trimester: limited data; theoretical risk. Second and third trimesters: may cause fetal bradycardia, hypoperfusion, and acidosis due to maternal hypotension. Avoid during pregnancy, especially in second and third trimesters. |
■ FDA Black Box Warning
Reye syndrome: Aspirin should not be used in children or teenagers with viral infections due to risk of Reye syndrome.
| Serious Effects |
Hypersensitivity to aspirin or NSAIDs; active bleeding; severe hepatic impairment; children with viral infections (Reye syndrome risk).
| Precautions | Increased risk of gastrointestinal bleeding; hypersensitivity reactions (e.g., asthma, urticaria); avoid use in severe hepatic impairment; caution in patients with history of peptic ulcer disease or bleeding disorders. |
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| Fetal Monitoring | Monitor maternal blood pressure and heart rate. For fetal monitoring, consider fetal heart rate monitoring during administration, especially if used near term. Assess for fetal distress if maternal hypotension occurs. |
| Fertility Effects | No human data on fertility. Animal studies: no impairment of fertility at doses up to 0.7 mg/kg/day. Potential impact on spermatogenesis based on antiarrhythmic properties, but clinical relevance unknown. |