Aspirin

Aspirin

Apo-ASA (CAN), Aspergum, Bayer, Easprin, Ecotrin, Empirin, Entrophen (CAN), Genprin, Halfprin 81, 1/2 Halfprin, Heartline, Norwich, Novasen (CAN), PMS-ASA (CAN), ZORprin

Buffered aspirin products:

Alka-Seltzer, Ascriptin, Asprimox, Bufferin, Buffex, Magnaprin

Pregnancy Category D

 

Drug classes:

Antipyretic

Analgesic (non-narcotic)

Anti-inflammatory

Antirheumatic

Antiplatelet

Salicylate

NSAID

 

Therapeutic actions

Analgesic and antirheumatic effects are attributable to aspirin's ability to inhibit the synthesis of prostaglandins, important mediators of inflammation. Antipyretic effects are not fully understood, but aspirin probably acts in the thermoregulatory center of the hypothalamus to block effects of endogenous pyrogen by inhibiting synthesis of the prostaglandin intermediary. Inhibition of platelet aggregation is attributable to the inhibition of platelet synthesis of thromboxane A₂, a potent vasoconstrictor and inducer of platelet aggregation. This effect occurs at low doses and lasts for the life of the platelet (8 days). Higher doses inhibit the synthesis of prostacyclin, a potent vasodilator and inhibitor of platelet aggregation.

 

Indications

· Mild to moderate pain

· Fever

· Inflammatory conditions--rheumatic fever, rheumatoid arthritis, osteoarthritis

· Reduction of risk of recurrent TIAs or stroke in males with history of TIA due to fibrin platelet emboli

· Reduction of risk of death or nonfatal MI in patients with history of infarction or unstable angina pectoris

· MI prophylaxis

· Unlabeled use: prophylaxis against cataract formation with long-term use

 

Contraindications

· Allergy to salicylates or NSAIDs (more common with nasal polyps, asthma, chronic urticaria); allergy to tartrazine (cross-sensitivity to aspirin is common); hemophilia, bleeding ulcers, hemorrhagic states, blood coagulation defects, hypoprothrombinemia, vitamin K deficiency (increased risk of bleeding); impaired renal function; chickenpox, influenza (risk of Reye's syndrome in children and teenagers); children with fever accompanied by dehydration; surgery scheduled within 1 wk; pregnancy (maternal anemia, antepartal and postpartal hemorrhage, prolonged gestation, and prolonged labor have been reported; readily crosses the placenta; possibly teratogenic; maternal ingestion of aspirin during late pregnancy has been associated with the following adverse fetal effects: low birth weight, increased intracranial hemorrhage, stillbirths, neonatal death); lactation.

 

 

Adverse effects

NSAIDs

Respiratory alkalosis, hyperpnea, tachypnea, hemorrhage, excitement, confusion, asterixis, pulmonary edema, convulsions, tetany, metabolic acidosis, fever, coma, cardiovascular collapse, Exacerbation of bronchospasm, rhinitis (with nasal polyps, asthma, rhinitis), Nausea, dyspepsia, heartburn, epigastric discomfort, anorexia, hepatotoxicity, Occult blood loss, hemostatic defect, Anaphylactoid reactions to anaphylactic shock, Dizziness, tinnitus, difficulty hearing, nausea, vomiting, diarrhea, mental confusion, lassitude (dose related)

Drug Interactions

· Increased risk of bleeding with oral anticoagulants, heparin

· Increased risk of GI ulceration with steroids, phenylbutazone, alcohol, NSAIDs

· Increased serum salicylate levels due to decreased salicylate excretion with urine acidifiers (ammonium chloride, ascorbic acid, methionine)

· Increased risk of salicylate toxicity with carbonic anhydrase inhibitors, furosemide

· Decreased serum salicylate levels with corticosteroids

· Decreased serum salicylate levels due to increased renal excretion of salicylates with acetazolamide, methazolamide, certain antacids, alkalinizers

· Decreased absorption of aspirin with nonabsorbable antacids

· Increased methotrexate levels and toxicity with aspirin

· Increased effects of valproic acid secondary to displacement from plasma protein sites

· Greater glucose lowering effect of sulfonylureas, insulin with large doses (> 2 g/day) of aspirin

· Decreased antihypertensive effect of captopril, beta-adrenergic blockers with salicylates; consider discontinuation of aspirin

· Decreased uricosuric effect of probenecid, sulfinpyrazone

· Possible decreased diuretic effects of spironolactone, furosemide (in patients with compromised renal function)

· Unexpected hypotension may occur with nitroglycerin

Nursing considerations

· Give drug with food or after meals if GI upset occurs.

· Give drug with full glass of water to reduce risk of tablet or capsule lodging in the esophagus.

· Do not crush, and ensure that patient does not chew sustained-release preparations.

· Do not use aspirin that has a strong vinegar-like odor.

· Institute emergency procedures if overdose occurs: gastric lavage, induction of emesis, activated charcoal, supportive therapy.