THERAPEUTICS

Brands

• Bayer Aspirin, Ecotrin, Halfprin, Heartline, Empirin, Alka-Seltzer, Asprimox, Magnaprin, Bufferin, Ascriptin, Aspergum, ZORprin

Generic?

• Yes

Class

• Antiplatelet agent, NSAID

Commonly Prescribed for

(FDA approved in bold)

• To reduce risk of recent myocardial infarction (MI), transient ischemic attack (TIA), ischemic stroke (IS) due to fibrin platelet emboli (aortic arch atheroma, intracranial artery severe stenosis, bioprosthetic heart valve, carotid/ vertebral arterial dissection)

• Angina (unstable or stable)

• Revascularization procedures: coronary artery bypass graft (CABG), angioplasty, and carotid endarterectomy

• Analgesic/antipyretic

• Rheumatoid disease: spondyloarthropathies, rheumatoid arthritis, osteoarthritis, pleurisy associated with systemic lupus erythematosus

• Reducing risk of stroke in high-risk populations, such as non-valvular atrial fibrillation, when anticoagulants are contraindicated

• Toxemia of pregnancy

• Kawasaki disease

• Polycythemia vera

How the Drug Works

• By irreversibly acetylating cyclo-oxygenase- 1 (COX-1), aspirin inhibits synthesis of thromboxane A2, a prostaglandin derivative that is a potent vasoconstrictor and inducer of platelet aggregation

• Irreversibly inhibits platelet aggregation even at low doses

• At larger doses, it interferes with COX-1 and COX-2 in arterial walls, affecting prostaglandin production. It counteracts fever by reducing prostaglandin E2 within the hypothalamus, and dilation of peripheral blood vessels, allowing dissipation of excess heat

How Long Until It Works

• A single dose of aspirin inhibits platelet aggregation for the life of the platelet (7–10 days). In pain, effective within 1–2 hours

If It Works

• Continue to use for prevention of MI, IS, or TIA, and for pain

If It Doesn't Work

• Only reduces risk of MI or IS. Warfarin is superior for cardiogenic stroke. Control all IS risk factors such as smoking, hyperlipidemia, and hypertension. For acute events, admit patients for treatment and diagnostic testing. Consider screening for aspirin resistance

Best Augmenting Combos for Partial Response or Treatment-Resistance

• Recent stroke/TIA due to severe (≥ 70%) stenosis of major intracranial artery: clopidogrel and aspirin for 90 days