- for mild pain, inflamation, RA, and prevention of stroke and DVT;
- adult: w/ pain and fever: 325-650mg q4hr PO, PR;
- rhuematoid arthritis: 3-12gm/day;
- check serum levels, therapeutic = 20-30 mg/dl;
- at high levels small increase may produce substantial increase in drug levels;
- note early signs of toxicity include: N,V, diaphoresis, flushed appearance, thirst, cephalgia, vertigo, diarrhea, rapid HR;
- risk reduction in DVT (see DVT):
- gastric irritation may be minimized by taking tablets after food or with antacids or by using enteric coated preparations;
- stroke risk & MI: platlet inhibiting activity: 325mg PO qd to 650mg PO bid,
- caution w/ PUD, asthma, bleeding tendencies, hyperuricemia (note: low doses of ASA - 1-2.5 gm/day);
- cause urate retention; high dose - 3-5 gm/day - are uricouric;
- may inhibit the effect of probenecid and sulfinpyrazone;
- use linked to Reye's syndrome; avoid use with viral illness in children;
- antipyretics: 10-15 mg/kg/dose q4hr upto 80 mg/kg/24hr;
- RA: 60-100 mg/kg/24hr divided q4-6hr (monitor serum levels to maintain between15-30 mg/dl);
- aspirin irreversibly inhibits cyclooxygenase by acetylation at its active site;
- cyclo-oxygenase is the enzyme that converts arachidonic acid to precursors of both Prostacyclin & throboxane;
- effect on platelets is due to recovery of cyclooxygenase production in endothelial cells and due to fact that platelets encounter orally given
aspirin in presystemic circulation before it is deacetylated in liver;
- platelets cannot produce cyclooxygenase, & Thromboxane synthesis recovers only as new platelets enter circulation.
- life of a platelet is about 8 to 11 days.
- cyclooxygenase is continuously produced in endothelial cells, and they will recover their ability to synthesize prostacyclin within a few hours;
- doses of 50 mg qd are sufficient to inhibit thromboxane A(sub 2) production
Review Article: Medical Progress: The Clinical Importance of Acquired Abnormalities of Platelet Function.
Current Concepts Review. Prophylaxis of Venous Thromboembolic Disease Following Hip and Knee Surgery.
Prevention of one-year vein-graft occlusion after aortocoronary-bypass surgery: a comparison of low-dose aspirin, low-dose aspirin plus dipyridamole, and oral anticoagulants. The CABADAS Research Group of the Interuniversity Cardiology Institute of The Netherlands.