Stahl's Essential Psychopharmacology Online
In Collaboration With
Aspirin (Acetylsalicylic Acid)
Therapeutics
Brands
• Bayer Aspirin, Ecotrin, Halfprin, Heartline, Empirin, Alka-Seltzer, Asprimox, Magnaprin, Bufferin, Ascriptin, Aspergum, ZORprin
Generic?
Yes
Class
• Antiplatelet agent, NSAID, anti-inflammatory
Commonly Prescribed for
(FDA approved in bold)
• To reduce risk of myocardial infarction (MI), transient ischemic attack (TIA) or ischemic stroke (IS) due to fibrin platelet
emboli
• Angina (unstable or stable)
• Revascularization procedures (coronary artery bypass graft (CABG), angioplasty, and carotid endarterectomy)
• Analgesic for mild-moderate pain for relief of headache, muscle aches and pains, toothache, arthritis, menstrual pain
• Fever
• Rheumatic conditions, such as 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
How the Drug Works
• By 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, interferes with cox-1 and -2 in arterial walls, interfering with prostaglandin production. Counteracts fever
by vasodilation of peripheral 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
• In
stroke prevention, there is no proven benefit to using clopidogrel in
combination with aspirin. In clinical trials, there
was no significant difference in IS
prevention, and AEs (mostly bleeding) were significantly higher
• Consider changing to dipyridamole-aspirin combination for IS prevention
• Pain: In acute migraine, add caffeine and/or acetaminophen, antiemetics, or triptans
Tests
• None required