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Pronunciation

(AS pir in)

Index Terms

  • Acetylsalicylic Acid
  • ASA
  • Baby Aspirin

Dosage Forms

Excipient information presented when available (limited, particularly for generics); consult specific product labeling. [DSC] = Discontinued product

Caplet, oral: 500 mg

Bayer Aspirin Extra Strength: 500 mg

Bayer Genuine Aspirin: 325 mg

Bayer Women's Low Dose Aspirin: 81 mg [contains elemental calcium 300 mg]

Caplet, oral [buffered]:

Ascriptin Maximum Strength: 500 mg [contains aluminum hydroxide, calcium carbonate, magnesium hydroxide]

Bayer Plus Extra Strength: 500 mg [contains calcium carbonate]

Caplet, enteric coated, oral:

Bayer Aspirin Regimen Regular Strength: 325 mg

Capsule Extended Release, oral:

Durlaza: 162.5 mg

Suppository, rectal: 300 mg (12s); 600 mg (12s)

Tablet, oral: 325 mg

Aspercin: 325 mg

Aspirtab: 325 mg

Bayer Genuine Aspirin: 325 mg

Tablet, oral [buffered]: 325 mg

Ascriptin Regular Strength: 325 mg [contains aluminum hydroxide, calcium carbonate, magnesium hydroxide]

Buffasal: 325 mg [contains magnesium oxide]

Bufferin: 325 mg [contains calcium carbonate, magnesium carbonate, magnesium oxide]

Bufferin Extra Strength: 500 mg [contains calcium carbonate, magnesium carbonate, magnesium oxide]

Buffinol: 324 mg [sugar free; contains magnesium oxide]

Tri-Buffered Aspirin: 325 mg [contains calcium carbonate, magnesium carbonate, magnesium oxide]

Tablet, chewable, oral: 81 mg

Bayer Aspirin Regimen Children's: 81 mg [cherry flavor]

Bayer Aspirin Regimen Children's: 81 mg [orange flavor]

St Joseph Adult Aspirin: 81 mg

Tablet, enteric coated, oral: 81 mg, 325 mg, 650 mg

Aspir-low: 81 mg

Bayer Aspirin Regimen Adult Low Strength: 81 mg

Ecotrin: 325 mg

Ecotrin Arthritis Strength: 500 mg

Ecotrin Low Strength: 81 mg

Halfprin: 81 mg [DSC]

St Joseph Adult Aspirin: 81 mg

Brand Names: U.S.

  • Ascriptin Maximum Strength [OTC]
  • Ascriptin Regular Strength [OTC]
  • Aspercin [OTC]
  • Aspir-low [OTC]
  • Aspirtab [OTC]
  • Bayer Aspirin Extra Strength [OTC]
  • Bayer Aspirin Regimen Adult Low Strength [OTC]
  • Bayer Aspirin Regimen Children's [OTC]
  • Bayer Aspirin Regimen Regular Strength [OTC]
  • Bayer Genuine Aspirin [OTC]
  • Bayer Plus Extra Strength [OTC]
  • Bayer Women's Low Dose Aspirin [OTC]
  • Buffasal [OTC]
  • Bufferin Extra Strength [OTC]
  • Bufferin [OTC]
  • Buffinol [OTC]
  • Durlaza
  • Ecotrin Arthritis Strength [OTC]
  • Ecotrin Low Strength [OTC]
  • Ecotrin [OTC]
  • Halfprin [OTC] [DSC]
  • St Joseph Adult Aspirin [OTC]
  • Tri-Buffered Aspirin [OTC]

Pharmacologic Category

  • Analgesic, Nonopioid
  • Antiplatelet Agent
  • Nonsteroidal Anti-inflammatory Drug (NSAID), Oral
  • Salicylate

Pharmacology

Irreversibly inhibits cyclooxygenase-1 and 2 (COX-1 and 2) enzymes, via acetylation, which results in decreased formation of prostaglandin precursors; irreversibly inhibits formation of prostaglandin derivative, thromboxane A2, via acetylation of platelet cyclooxygenase, thus inhibiting platelet aggregation; has antipyretic, analgesic, and anti-inflammatory properties

Absorption

Immediate release: Rapidly absorbed in stomach and upper intestine (Eikelboom, 2012); Extended-release capsule: Rate of absorption is dependent upon food, alcohol, and gastric pH.

Distribution

Vd: 10 L; readily distributes into most body fluids and tissues; hydrolyzed to salicylate (active) by esterases in the GI mucosa, red blood cells, synovial fluid and blood

Metabolism

Hydrolyzed to salicylate (active) by esterases in GI mucosa, red blood cells, synovial fluid, and blood; metabolism of salicylate occurs primarily by hepatic conjugation; metabolic pathways are saturable

Excretion

Urine (75% as salicyluric acid, 10% as salicylic acid)

Onset of Action

Immediate release: Platelet inhibition: Within 1 hour (nonenteric-coated). Onset of enteric-coated aspirin expected to be delayed (Eikelboom, 2012). Note: Chewing nonenteric-coated or enteric-coated tablets results in inhibition of platelet aggregation within 20 minutes; therefore, nonenteric-coated tablets should be chewed in settings where a more rapid onset is required (eg, acute MI) and enteric-coated tablets may be chewed when a rapid effect is required and immediate release nonenteric-coated tablets are not available (Eikelboom, 2012; Feldman, 1999; Sai, 2011).

Time to Peak

Serum: Immediate release: ~1 to 2 hours (nonenteric-coated), 3 to 4 hours (enteric-coated) (Eikelboom, 2012); Extended-release capsule: ~2 hours. Note: Chewing nonenteric-coated tablets results in a time to peak concentration of 20 minutes (Feldman, 1999). Chewing enteric-coated tablets results in a time to peak concentration of 2 hours (Sai, 2011).

Duration of Action

Immediate release: 4 to 6 hours; however, platelet inhibitory effects last the lifetime of the platelet (~10 days) due to its irreversible inhibition of platelet COX-1 (Eikelboom, 2012).

Half-Life Elimination

Parent drug: Plasma concentration: 15 to 20 minutes; Salicylates (dose dependent): 3 hours at lower doses (300 to 600 mg), 5 to 6 hours (after 1 g), 10 hours with higher doses

Protein Binding

Concentration dependent; as salicylate concentration increases, protein binding decreases: ~90% to 94% (to albumin) at concentrations ≤80 mcg/mL (Rosenberg, 1981; Juurlink, 2015); ~30% with concentrations seen in overdose (Juurlink, 2015).

Use: Labeled Indications

Immediate release:

Analgesic/Antipyretic: For the temporary relief of headache, pain, and fever caused by colds, muscle aches and pains, menstrual pain, toothache pain, and minor aches and pains of arthritis.

Revascularization procedures: In patients who have undergone revascularization procedures (ie, coronary artery bypass graft [CABG], percutaneous transluminal coronary angioplasty, or carotid endarterectomy).

Rheumatoid disease: For the relief of the signs and symptoms of rheumatoid arthritis (RA), juvenile idiopathic arthritis (formerly called juvenile RA), osteoarthritis, spondyloarthropathies, and arthritis and pleurisy associated with systemic lupus erythematosus.

Vascular indications (ischemic stroke, transient ischemic attack, acute myocardial infarction, prevention of recurrent myocardial infarction, unstable angina, and chronic stable angina): To reduce the combined risk of death and nonfatal stroke in patients who have had ischemic stroke or transient ischemia of the brain due to fibrin platelet emboli; to reduce the risk of vascular mortality in patients with a suspected acute myocardial infarction (MI); to reduce the combined risk of death and nonfatal MI in patients with a previous MI or unstable angina; to reduce the combined risk of MI and sudden death in patients with chronic stable angina.

Extended-release capsules:

Chronic coronary artery disease: To reduce the risk of death and MI in patients with chronic coronary artery disease (eg, history of MI, unstable angina, or chronic stable angina).

History of ischemic stroke or transient ischemic attack: To reduce the risk of death and recurrent stroke in patients who have had an ischemic stroke or transient ischemic attack (TIA).

Limitations of use: Do not use extended-release capsules in situations for which a rapid onset of action is required (such as acute treatment of MI or before percutaneous coronary intervention); use immediate-release formulations instead.

Use: Unlabeled

Prevention of preeclampsia, colorectal cancer; Kawasaki disease; prevention of thromboembolism associated with atrial fibrillation in patients not candidates for warfarin; pericarditis including pericarditis associated with MI; thromboprophylaxis for aortic valve repair, Blalock-Taussig shunt placement, carotid artery stenosis, coronary artery disease, Fontan surgery, peripheral arterial occlusive disease, peripheral artery percutaneous transluminal angioplasty, peripheral artery bypass graft surgery, prosthetic valves, ventricular assist device (VAD) placement

Contraindications

Hypersensitivity to NSAIDs; patients with asthma, rhinitis, and nasal polyps; use in children or teenagers for viral infections, with or without fever.

Documentation of allergenic cross-reactivity for salicylates is limited. However, because of similarities in chemical structure and/or pharmacologic actions, the possibility of cross-sensitivity cannot be ruled out with certainty.

Dosing: Adult

Note: For most cardiovascular uses, typical maintenance dosing of aspirin is 81 mg once daily. Manufacturer recommended dosing for some indications have been superseded by more recent guideline recommended doses and therefore manufacturer recommended dosing may not be represented; terminologies may also differ from manufacturer’s prescribing information.

Acute coronary syndrome (ST- elevation myocardial infarction [STEMI], non-ST-elevation acute coronary syndromes [NSTE-ACS]): Oral:

Initial: 162 to 325 mg given on presentation (patient should chew nonenteric-coated aspirin especially if not taking before presentation) (ACC/AHA [Amsterdam 2014]; ACCF/AHA [O'Gara 2013]); for patients unable to take oral, may use a rectal suppository dose of 600 mg (Maalouf 2009).

Maintenance (secondary prevention): 81 to 325 mg once daily continued indefinitely; when aspirin is used with ticagrelor, the recommended maintenance dose of aspirin is 81 mg/day (ACC/AHA [Amsterdam 2014]; ACCF/AHA [O’Gara 2013]) According to the STEMI guidelines, 81 mg once daily is preferred (ACCF/AHA [O’Gara 2013]).

Concomitant antiplatelet therapy:

STEMI: Aspirin is recommended in combination with either clopidogrel, prasugrel, or ticagrelor given as early as possible or at time of PCI. In addition to dual antiplatelet therapy, parenteral anticoagulant therapy is indicated. Post-PCI stenting, consult clinical practice guidelines for recommended duration of maintenance antiplatelet therapy depending on type of stenting (ACCF/AHA [O'Gara 2013]).

NSTE-ACS:

If early-invasive strategy chosen: Aspirin is recommended in combination with either clopidogrel or ticagrelor. In addition to dual antiplatelet therapy, parenteral anticoagulant therapy is indicated. In select high-risk patients (ie, troponin positive), an IV GP IIb/IIIa inhibitor may be considered as part of initial antiplatelet therapy (if given before PCI, eptifibatide and tirofiban are preferred agents). In patients post-PCI with stenting (bare metal or drug-eluting stent), aspirin should be given with either clopidogrel, ticagrelor, or prasugrel for at least 12 months (ACC/AHA [Amsterdam 2014])

If ischemia-guided strategy (ie, noninvasive strategy) chosen: Aspirin is recommended in combination with clopidogrel or ticagrelor for up to 12 months In addition to dual antiplatelet therapy, parenteral anticoagulant therapy is indicated. (ACC/AHA [Amsterdam 2014]).

Analgesic and antipyretic:

Oral: Immediate release: 325 to 650 mg as needed every 4 hours or 975 mg as needed every 6 hours or 500 to 1,000 mg as needed every 4 to 6 hours for no more than 10 days or as directed by health care provider; maximum daily dose: 4 g/day.

Rectal: 300 to 600 mg every 4 hours for no more than 10 days or as directed by health care provider

Anti-inflammatory (off-label dosing): Note: The use of non-aspirin NSAIDs has largely supplanted the use of aspirin for osteoarthritis, rheumatoid arthritis, and other inflammatory arthritides.

Immediate release: Oral: Usual maintenance dose: 2.1 to 7.3 g/day in divided doses (individualize dose); monitor serum salicylate concentrations especially when symptoms of salicylism (eg, tinnitus) appear; adjust dose accordingly (Csuka, 1989).

Aortic valve repair (off-label use): Immediate release: Oral: 50 to 100 mg once daily (ACCP [Guyatt 2012])

Atrial fibrillation (to prevent thromboembolism in patients not candidates for oral anticoagulation or at low risk of ischemic stroke [CHA2DS2-VASc score of 1]) (off-label use): Immediate release: Oral: 75 to 325 mg once daily (AHA/ACC/HRS [January 2014]; AHA/ASA [Furie 2011]). Note: Combination therapy with clopidogrel has been suggested over aspirin alone for those patients who are unsuitable for or choose not to take oral anticoagulant for reasons other than concerns for bleeding (ACCP [Guyatt 2012]).

As an alternative to adjusted-dose warfarin in patients with atrial fibrillation and mitral stenosis: 75 to 325 mg once daily with (preferred) or without clopidogrel (ACCP [Guyatt 2012])

Carotid artery stenosis (asymptomatic) (off-label use): Immediate release: Oral: 75 to 100 mg once daily (ACCP [Alonso-Coello, 2012]). Note: The addition of statin therapy has also been recommended for asymptomatic carotid stenosis (AHA/ASA [Meschia, 2014]). When symptomatic, the use of clopidogrel or aspirin/extended-release dipyridamole has been suggested over aspirin alone (ACCP [Alonso-Coello 2012]).

Carotid endarterectomy (off-label dosing): Immediate release: Oral: 75 to 100 mg once daily (ACCP [Alonso-Coello 2012]; AHA [Biller 1998]). The use of clopidogrel or aspirin/extended-release dipyridamole has been suggested over aspirin alone (ACCP [Alonso-Coello 2012]).

Colorectal cancer risk reduction (off-label use): Note: The optimal dose and duration of therapy for colorectal cancer risk reduction are unknown. Consider risk versus benefit ratio when initiating aspirin for this indication.

Primary/Secondary prevention: Immediate release: Oral: 75 to 325 mg once daily (Rothwell, 2010; Sandler, 2003; Ye, 2013)

Hereditary nonpolyposis colon cancer (HNPCC; Lynch Syndrome) carriers: Immediate release: Oral: 600 mg once daily for at least 2 years (ASCO [Stoffel 2014]; Burn, 2011)

Coronary artery disease (CAD), established or chronic:

Immediate release (off-label dosing): Oral: 75 to 100 mg once daily (ACCP [Guyatt 2012])

Extended release capsule: Oral: 162.5 mg once daily

Percutaneous coronary intervention (PCI) (off-label dosing): Immediate release: Oral:

Non-emergent PCI: Preprocedure: 81 to 325 mg (325 mg [nonenteric coated] in aspirin-naive patients) starting at least 2 hours (preferably 24 hours) before procedure. Postprocedure: 81 mg once daily continued indefinitely (in combination with a P2Y12 inhibitor [eg, clopidogrel, prasugrel, ticagrelor] up to 12 months) (ACCF/AHA/SCAI [Levine 2011])

Primary PCI: Preprocedure: 162 to 325 mg as early as possible prior to procedure; 325 mg preferred. Postprocedure: 81 mg once daily continued indefinitely (in combination with a P2Y12 inhibitor [eg, clopidogrel] for at least 14 days and up to 12 months) (ACCF/AHA [O'Gara 2013]).

Alternatively, in patients who have undergone elective PCI with either bare metal or drug-eluting stent placement: The American College of Chest Physicians recommends the use of 75 to 325 mg once daily (in combination with clopidogrel) for 1 month in patients receiving a bare metal stent or 3 to 6 months (dependent upon drug eluting stent type) followed by 75 to 100 mg once daily (in combination with clopidogrel) for up to 12 months. For patients who underwent PCI but did not have stent placement, 75 to 325 mg once daily (in combination with clopidogrel) for 1 month is recommended. In either case, single antiplatelet therapy (either aspirin or clopidogrel) is recommended indefinitely (ACCP [Guyatt 2012]).

Pericarditis (off-label use): Immediate release: Oral: Initial: 2.4 to 3.6 g daily in 3 to 4 divided doses; usual maintenance: 3.6 to 5.4 g daily in divided doses; gradually taper over 2- to 3-week period as appropriate (Imazio, 2004; Imazio, 2009).

Pericarditis in association with myocardial infarction (off-label use): Immediate release: Oral: Initial: 650 mg 4 times daily; may increase after 24 hours to 975 mg 4 times daily if necessary (ACCF/AHA [O'Gara 2013]; Berman, 1981).

Peripheral arterial disease (off-label use): Immediate release: Oral: 75 to 100 mg once daily (ACCP [Guyatt 2012]) or 75 to 325 mg once daily; may use in conjunction with clopidogrel in those who are not at an increased risk of bleeding but are of high cardiovascular risk. Note: These recommendations also pertain to those with intermittent claudication or critical limb ischemia, prior lower extremity revascularization, or prior amputation for lower extremity ischemia (Rooke, 2011).

Peripheral artery percutaneous transluminal angioplasty (with or without stenting) or peripheral artery bypass graft surgery, postprocedure (off-label use): Immediate release: Oral: 75 to 100 mg once daily (ACCP [Guyatt 2012]). Note: For below-knee bypass graft surgery with prosthetic grafts, combine with clopidogrel (ACCP [Guyatt 2012]).

Polycythemia vera (off-label use): Immediate release: Oral: 75 or 100 mg once daily. In pregnant women, administer 75 mg once daily throughout pregnancy and for 6 weeks after delivery (Barbui, 2006; McMullin, 2005).

Preeclampsia prevention (women at risk) (off-label use): Immediate release: Oral: 75 to 100 mg once daily starting in the second trimester (ACCP [Guyatt 2012]; USPSTF [LeFevre 2014]) or 60 to 80 mg once daily beginning late in the first trimester (ACOG, 2013).

Prevention (primary) of cardiovascular disease (off-label use): Immediate release: Oral:

American College of Chest Physicians: Select individuals ≥50 years of age (without symptomatic cardiovascular disease): 75 to 100 mg once daily (ACCP [Vandvik 2012])

American Diabetes Association: Individuals ≥50 years of age with diabetes type 1 or 2 who are increased cardiovascular risk (10-year risk >10%): 75 to 162 mg once daily (ADA 2016)

Prevention (secondary) after coronary artery bypass graft (CABG) surgery (off-label dosing): Immediate release: Oral: 81 to 325 mg once daily administered preoperatively and within 6 hours postoperatively; continue indefinitely. Following off-pump CABG, administer aspirin 81 to 162 mg in combination with clopidogrel for 12 months (AHA [Kulik 2015]).

Prosthetic heart valve (thromboprophylaxis) (off-label use): Immediate release: Oral:

Bioprosthetic aortic valve (patient in normal sinus rhythm): 50 to 100 mg once daily (ACCP [Guyatt 2012]).

Bioprosthetic mitral valve: 50 to 100 mg once daily after 3 months of anticoagulation with warfarin (ACCP [Guyatt 2012]).

Mechanical aortic or mitral valve:

Low risk of bleeding: 50 to 100 mg once daily (in combination with warfarin) (ACCP [Guyatt 2012])

History of thromboembolism while receiving oral anticoagulants: 75 to 100 mg once daily (in combination with warfarin) (Furie, 2011)

Transcatheter aortic bioprosthetic valve: 50 to 100 mg once daily (in combination with clopidogrel) (ACCP [Guyatt 2012])

Pregnant women, mechanical or bioprosthetic: 75 to 100 mg once daily during the second and third trimesters (when used for mechanical prosthetic valve, combine with warfarin) (AHA/ACC [Nishimura 2014]).

Stroke/TIA: Oral:

Acute ischemic stroke/TIA:

Immediate release (off-label dosing): Initial: 160 to 325 mg within 48 hours of stroke/TIA onset, followed by 75 to 100 mg once daily (ACCP [Guyatt 2012]). The AHA/ASA recommends an initial dose of 325 mg within 24 to 48 hours after stroke; do not administer aspirin within 24 hours after administration of alteplase (Jauch, 2013).

Extended-release capsule: Maintenance (secondary prevention): 162.5 mg once daily. Note: Not for initial dosing during acute ischemic stroke or TIA (use immediate release)

Cardioembolic, secondary prevention (oral anticoagulation unsuitable) (off-label dosing: Immediate release: 75 to 100 mg once daily (in combination with clopidogrel) (ACCP [Guyatt 2012]; The ACTIVE Investigators [Connolly 2009])

Cryptogenic with patent foramen ovale (PFO) or atrial septal aneurysm (off-label use): Immediate release: 50 to 100 mg once daily (ACCP [Guyatt 2012])

Noncardioembolic, secondary prevention (off-label use): Immediate release: 75 to 325 mg once daily (Smith, 2011) or 75 to 100 mg once daily (ACCP [Guyatt 2012]). Note: Combination aspirin/extended release dipyridamole or clopidogrel is preferred over aspirin alone (ACCP [Guyatt 2012]).

Women at high risk for first stroke, primary prevention: Immediate release: 81 mg once daily or 100 mg every other day (AHA/ASA [Meschia 2014]).

Dosing: Geriatric

Refer to adult dosing.

Dosing: Pediatric

Note: Do not use aspirin in children <12 years (APS, 2008) and adolescents (per manufacturer) who have or who are recovering from chickenpox or flu symptoms due to the association with Reye's syndrome (APS, 2008).

Analgesic: Immediate release:

Infants, Children, and Adolescents weighing <50 kg (off-label use): Oral, rectal: 10 to 15 mg/kg/dose every 4 to 6 hours; maximum daily dose: The lesser value of either 90 mg/kg/day or 4 g/day (APS, 2008)

Children ≥12 years and Adolescents weighing ≥50 kg:

Oral: 325 to 650 mg as needed every 4 hours or 975 mg as needed every 6 hours or 500 to 1,000 mg as needed every 4 to 6 hours for no more than 10 days or as directed by health care provider; maximum daily dose: 4 g/day

Rectal: 300 to 600 mg every 4 hours for no more than 10 days or as directed by health care provider

Anti-inflammatory (off-label use): Immediate release: Oral: Initial: 60 to 90 mg/kg/day in divided doses; usual maintenance: 80 to 100 mg/kg/day divided every 6 to 8 hours; monitor serum concentrations

Antiplatelet effects (off-label use): Adequate pediatric studies have not been performed; pediatric dosage is derived from adult studies and clinical experience and is not well established. Doses are typically rounded to a convenient amount (eg, 1/2 of 81 mg tablet).

Acute ischemic stroke (AIS) (off-label use): Immediate release: Oral:

Noncardioembolic: 1 to 5 mg/kg/dose once daily for ≥2 years; patients with recurrent AIS or TIAs should be transitioned to clopidogrel, LMWH, or warfarin (ACCP [Monagle 2012])

Secondary to Moyamoya and non-Moyamoya vasculopathy: 1 to 5 mg/kg/dose once daily. Note: In non-Moyamoya vasculopathy, continue aspirin for 3 months, with subsequent use guided by repeat cerebrovascular imaging (ACCP [Monagle 2012]).

Norwood, Fontan surgery (postoperative) (primary prophylaxis) (off-label use): Immediate release: Oral: 1 to 5 mg/kg/dose once daily (ACCP [Monagle 2011]; AHA [Giglia 2013])

Prosthetic heart valve (off-label use): Immediate release: Oral:

Bioprosthetic aortic valve (in normal sinus rhythm): 1 to 5 mg/kg/dose once daily (ACCP [Guyatt 2012]; ACCP [Monagle 2012])

Mechanical aortic and/or mitral valve: Low-dose aspirin (eg, 1 to 5 mg/kg/day) combined with vitamin K antagonist (eg, warfarin) is recommended as first-line antithrombotic therapy (ACCP [Guyatt 2012]). Alternative regimens: 6 to 20 mg/kg/dose once daily in combination with dipyridamole (Bradley 1985; El Makhlouf 1987; LeBlanc 1993; Serra 1987; Solymar 1991)

Shunts: Blalock-Taussig or Glenn (primary prophylaxis) (off-label use): Immediate release: Oral: 1 to 5 mg/kg/dose once daily (AHA [Giglia 2013]; ACCP [Monagle 2012])

Transcatheter Atrial Septal Defect (ASD) or Ventricular Septal Defect (VSD) devices (postprocedure prophylaxis) (off-label use): Immediate release: Oral: 1 to 5 mg/kg/dose once daily starting one to several days prior to implantation and continued for at least 6 months. For older children and adolescents, after device closure of ASD, an additional anticoagulant may be given with aspirin for 3 to 6 months, but the aspirin should continue for at least 6 months (AHA [Giglia 2013]).

Ventricular assist device (VAD) placement (off-label use): Immediate release: Oral: 1 to 5 mg/kg/dose once daily initiated within 72 hours of VAD placement; should be used with heparin (initiated between 8 to 48 hours following implantation) (ACCP [Monagle 2012]).

Kawasaki disease (off-label use): Immediate release: Oral: 80 to 100 mg/kg/day divided every 6 hours for up to 14 days (until fever resolves for at least 48 hours); then decrease dose to 1 to 5 mg/kg/day once daily (AHA and AAP suggest 3 to 5 mg/kg/day). Combine initial high-dose treatment with IV immune globulin within first 10 days of symptom onset. In patients without coronary artery abnormalities, give lower dose for at least 6 to 8 weeks. In patients with coronary artery abnormalities, low-dose aspirin should be continued indefinitely (in combination with warfarin) (ACCP [Monagle 2012]; AHA [Giglia 2013]; Newburger, 2004; Red Book [AAP 2015]).

Rheumatic fever (off-label use): Limited data available: Infants, Children, and Adolescents: Oral: Initial: 100 mg/kg/day divided into 4 to 5 doses; if response inadequate, may increase dose to 125 mg/kg/day; continue for 2 weeks; then decrease dose to 60 to 70 mg/kg/day in divided doses for an additional 3 to 6 weeks (WHO Guidelines 2004)

Migratory polyarthritis, with carditis without cardiomegaly or congestive heart failure: Initial: 100 mg/kg/day in 4 divided doses for 3 to 5 days, followed by 75 mg/kg/day in 4 divided doses for 4 weeks (Kliegman 2011)

Carditis and cardiomegaly or congestive heart failure: At the beginning of the tapering of the prednisone dose, aspirin should be started at 75 mg/kg/day in 4 divided doses for 6 weeks (Kliegman 2011)

Dosing: Renal Impairment

Analgesia or anti-inflammatory uses: The manufacturer recommends avoiding in patients with CrCl <10 mL/minute. However, may use with caution and monitor renal function or consider the use of an alternative analgesic/anti-inflammatory agent (NKF [Henrich 1996], Whelton 2000).

Antiplatelet uses: The manufacturer recommends avoiding in patients with CrCl <10 mL/minute. However, in general, the benefit of low-dose aspirin outweighs any risk associated with nephropathy or other adverse effects even in the setting of severe renal impairment; the recommended aspirin dose should not be reduced in any patient with suspected or documented ACS, other cardiovascular disease, or other antithrombotic indication (Fernandez 2001, Harter 1979, Summaria 2015). In patients with diabetes and chronic kidney disease or in dialysis patients, the National Kidney Foundation recommends the use of antithrombotic doses of aspirin (ie, 75 to 162 mg daily) for prevention and management of ischemic heart disease or primary prevention of atherosclerotic disease (KDOQI 2005, KDOQI 2007).

Hemodialysis: Dialyzable (concentration dependent; higher salicylate concentrations are more readily dialyzable: 50% to 60%) (Juurlink 2015; Rosenberg 1981); consider administration after hemodialysis on dialysis days (Aronoff 2007).

Dosing: Hepatic Impairment

Avoid use in severe liver disease.

Administration

Oral:

Immediate-release tablets: Do not crush enteric-coated tablet. Administer with food or a full glass of water to minimize GI distress. In situations for which a rapid onset of action is required (eg, acute treatment of MI), have patient chew immediate-release tablet.

Extended-release capsules: Do not cut, crush, or chew. Administer with a full glass of water at the same time each day. Do not administer 2 hours before or 1 hour after alcohol consumption.

Rectal: Remove suppository from plastic packet and insert into rectum as far as possible.

Storage

Store oral dosage forms (caplets, tablets, capsules) at room temperature; protect from moisture; see product-specific labeling for details. Keep suppositories in refrigerator; do not freeze. Hydrolysis of aspirin occurs upon exposure to water or moist air, resulting in salicylate and acetate, which possess a vinegar-like odor. Do not use if a strong odor is present.

Drug Interactions

ACE Inhibitors: Salicylates may enhance the nephrotoxic effect of ACE Inhibitors. Salicylates may diminish the therapeutic effect of ACE Inhibitors. Monitor therapy

Agents with Antiplatelet Properties (e.g., P2Y12 inhibitors, NSAIDs, SSRIs, etc.): May enhance the adverse/toxic effect of Salicylates. Increased risk of bleeding may result. Monitor therapy

Agents with Antiplatelet Properties (e.g., P2Y12 inhibitors, NSAIDs, SSRIs, etc.): May enhance the antiplatelet effect of other Agents with Antiplatelet Properties. Monitor therapy

Ajmaline: Salicylates may enhance the adverse/toxic effect of Ajmaline. Specifically, the risk for cholestasis may be increased. Monitor therapy

Alcohol (Ethyl): May enhance the adverse/toxic effect of Aspirin. Specifically, alcohol may increase the bleeding risk of aspirin. Alcohol (Ethyl) may diminish the therapeutic effect of Aspirin. Specifically, alcohol may interfere with the controlled release mechanism of extended release aspirin. Management: Monitor patients who drink 3 or more alcoholic drinks a day for increased bleeding while taking aspirin. Counsel patients about the risk of bleeding and discourage such consumption. Give extended release aspirin 2 hours before, or 1 hour after, alcohol. Consider therapy modification

Alendronate: Aspirin may enhance the adverse/toxic effect of Alendronate. Specifically, the incidence of upper gastrointestinal adverse events may be increased Monitor therapy

Ammonium Chloride: May increase the serum concentration of Salicylates. Monitor therapy

Anticoagulants: Agents with Antiplatelet Properties may enhance the anticoagulant effect of Anticoagulants. Monitor therapy

Anticoagulants: Salicylates may enhance the anticoagulant effect of Anticoagulants. Monitor therapy

Antidepressants (Tricyclic, Tertiary Amine): May enhance the antiplatelet effect of Aspirin. Monitor therapy

Apixaban: Aspirin may enhance the adverse/toxic effect of Apixaban. Specifically, the risk for bleeding may be increased. Management: Carefully consider risks and benefits of this combination and monitor closely. Consider therapy modification

Benzbromarone: Salicylates may diminish the therapeutic effect of Benzbromarone. Monitor therapy

Blood Glucose Lowering Agents: Salicylates may enhance the hypoglycemic effect of Blood Glucose Lowering Agents. Monitor therapy

Calcium Channel Blockers (Nondihydropyridine): May enhance the antiplatelet effect of Aspirin. Monitor therapy

Carbonic Anhydrase Inhibitors: Salicylates may enhance the adverse/toxic effect of Carbonic Anhydrase Inhibitors. Salicylate toxicity might be enhanced by this same combination. Management: Avoid these combinations when possible.Dichlorphenamide use with high-dose aspirin as contraindicated. If another combination is used, monitor patients closely for adverse effects. Tachypnea, anorexia, lethargy, and coma have been reported. Exceptions: Brinzolamide; Dorzolamide. Consider therapy modification

Carisoprodol: Aspirin may increase serum concentrations of the active metabolite(s) of Carisoprodol. Specifically, Meprobamate concentrations may be increased. Aspirin may decrease the serum concentration of Carisoprodol. Monitor therapy

Cephalothin: Agents with Antiplatelet Properties may enhance the adverse/toxic effect of Cephalothin. Specifically, the risk for bleeding may be increased. Monitor therapy

Collagenase (Systemic): Agents with Antiplatelet Properties may enhance the adverse/toxic effect of Collagenase (Systemic). Specifically, the risk of injection site bruising and/or bleeding may be increased. Monitor therapy

Corticosteroids (Systemic): Salicylates may enhance the adverse/toxic effect of Corticosteroids (Systemic). These specifically include gastrointestinal ulceration and bleeding. Corticosteroids (Systemic) may decrease the serum concentration of Salicylates. Withdrawal of corticosteroids may result in salicylate toxicity. Monitor therapy

Dabigatran Etexilate: Aspirin may enhance the adverse/toxic effect of Dabigatran Etexilate. Specifically, the risk for bleeding may be increased. Management: Carefully consider risks and benefits of this combination and monitor closely; Canadian labeling states that low dose aspirin could be considered, but the use of antiplatelets are not recommended for stroke prevention in patients with atrial fibrillation. Consider therapy modification

Dasatinib: May enhance the anticoagulant effect of Agents with Antiplatelet Properties. Monitor therapy

Deoxycholic Acid: Agents with Antiplatelet Properties may enhance the adverse/toxic effect of Deoxycholic Acid. Specifically, the risk for bleeding or bruising in the treatment area may be increased. Monitor therapy

Dexketoprofen: Salicylates may enhance the adverse/toxic effect of Dexketoprofen. Dexketoprofen may diminish the therapeutic effect of Salicylates. Salicylates may decrease the serum concentration of Dexketoprofen. Management: The use of high-dose salicylates (3 g/day or more in adults) together with dexketoprofen is inadvisable. Consider administering dexketoprofen 30-120 min after or at least 8 hrs before cardioprotective doses of aspirin to minimize any possible interaction. Avoid combination

Edoxaban: Aspirin may enhance the adverse/toxic effect of Edoxaban. Specifically, the risk of bleeding may be increased. Aspirin may increase the serum concentration of Edoxaban. Management: Carefully consider the anticipated risks and benefits of this combination. If combined, increased monitoring for bleeding is recommended. Consider therapy modification

Floctafenine: May enhance the adverse/toxic effect of Aspirin. An increased risk of bleeding may be associated with use of this combination. Floctafenine may diminish the cardioprotective effect of Aspirin. Avoid combination

Ginkgo Biloba: May enhance the anticoagulant effect of Salicylates. Management: Consider alternatives to this combination of agents. Monitor for signs and symptoms of bleeding (especially intracranial bleeding) if salicylates are used in combination with ginkgo biloba. Consider therapy modification

Glucosamine: May enhance the antiplatelet effect of Agents with Antiplatelet Properties. Monitor therapy

Heparin: Aspirin may enhance the anticoagulant effect of Heparin. Monitor therapy

Herbs (Anticoagulant/Antiplatelet Properties) (eg, Alfalfa, Anise, Bilberry): May enhance the adverse/toxic effect of Agents with Antiplatelet Properties. Bleeding may occur. Consider therapy modification

Herbs (Anticoagulant/Antiplatelet Properties) (eg, Alfalfa, Anise, Bilberry): May enhance the adverse/toxic effect of Salicylates. Bleeding may occur. Consider therapy modification

Hyaluronidase: Salicylates may diminish the therapeutic effect of Hyaluronidase. Management: Patients receiving salicylates (particularly at larger doses) may not experience the desired clinical response to standard doses of hyaluronidase. Larger doses of hyaluronidase may be required. Consider therapy modification

Ibritumomab: Agents with Antiplatelet Properties may enhance the adverse/toxic effect of Ibritumomab. Both agents may contribute to impaired platelet function and an increased risk of bleeding. Monitor therapy

Ibrutinib: May enhance the adverse/toxic effect of Agents with Antiplatelet Properties. Monitor therapy

Influenza Virus Vaccine (Live/Attenuated): May enhance the adverse/toxic effect of Salicylates. Specifically, Reye's syndrome may develop. Avoid combination

Ketorolac (Nasal): May enhance the adverse/toxic effect of Aspirin. An increased risk of bleeding may be associated with use of this combination. Ketorolac (Nasal) may diminish the cardioprotective effect of Aspirin. Avoid combination

Ketorolac (Systemic): May enhance the adverse/toxic effect of Aspirin. An increased risk of bleeding may be associated with use of this combination. Ketorolac (Systemic) may diminish the cardioprotective effect of Aspirin. Avoid combination

Lesinurad: Aspirin may diminish the therapeutic effect of Lesinurad. Monitor therapy

Limaprost: May enhance the antiplatelet effect of Agents with Antiplatelet Properties. Monitor therapy

Loop Diuretics: Salicylates may diminish the diuretic effect of Loop Diuretics. Loop Diuretics may increase the serum concentration of Salicylates. Monitor therapy

Methotrexate: Salicylates may increase the serum concentration of Methotrexate. Salicylate doses used for prophylaxis of cardiovascular events are not likely to be of concern. Consider therapy modification

Multivitamins/Fluoride (with ADE): May enhance the antiplatelet effect of Aspirin. Aspirin may decrease the serum concentration of Multivitamins/Fluoride (with ADE). Specifically, aspirin may decrease the absorption of ascorbic acid. Monitor therapy

Multivitamins/Minerals (with ADEK, Folate, Iron): May enhance the antiplatelet effect of Aspirin. Aspirin may decrease the serum concentration of Multivitamins/Minerals (with ADEK, Folate, Iron). Specifically, aspirin may decrease absorption of ascorbic acid. Monitor therapy

Multivitamins/Minerals (with AE, No Iron): May enhance the antiplatelet effect of Aspirin. Aspirin may decrease the serum concentration of Multivitamins/Minerals (with AE, No Iron). Specifically, aspirin may decrease the absorption of ascorbic acid. Monitor therapy

Nicorandil: Aspirin may enhance the adverse/toxic effect of Nicorandil. Specifically, the risk of gastrointestinal ulceration and hemorrhage may be increased. Monitor therapy

NSAID (COX-2 Inhibitor): Aspirin may enhance the adverse/toxic effect of NSAID (COX-2 Inhibitor). Management: Concurrent use of aspirin at doses beyond cardioprotective levels is not recommended. While concurrent use of low-dose aspirin with a COX-2 inhibitor is permissable, patients should be monitored closely for signs/symptoms of GI ulceration/bleeding. Consider therapy modification

NSAID (Nonselective): May enhance the adverse/toxic effect of Salicylates. An increased risk of bleeding may be associated with use of this combination. NSAID (Nonselective) may diminish the cardioprotective effect of Salicylates. Salicylates may decrease the serum concentration of NSAID (Nonselective). Consider therapy modification

Obinutuzumab: Agents with Antiplatelet Properties may enhance the adverse/toxic effect of Obinutuzumab. Specifically, the risk of serious bleeding-related events may be increased. Monitor therapy

Omacetaxine: Aspirin may enhance the adverse/toxic effect of Omacetaxine. Specifically, the risk for bleeding-related events may be increased. Management: Avoid concurrent use of aspirin with omacetaxine in patients with a platelet count of less than 50,000/uL. Avoid combination

Omega-3 Fatty Acids: May enhance the antiplatelet effect of Agents with Antiplatelet Properties. Monitor therapy

Pentosan Polysulfate Sodium: May enhance the adverse/toxic effect of Agents with Antiplatelet Properties. Specifically, the risk of bleeding may be increased by concurrent use of these agents. Monitor therapy

Pentoxifylline: May enhance the antiplatelet effect of Agents with Antiplatelet Properties. Monitor therapy

Potassium Acid Phosphate: May increase the serum concentration of Salicylates. Monitor therapy

PRALAtrexate: Salicylates may increase the serum concentration of PRALAtrexate. Salicylate doses used for prophylaxis of cardiovascular events are unlikely to be of concern. Consider therapy modification

Probenecid: Salicylates may diminish the therapeutic effect of Probenecid. Monitor therapy

Prostacyclin Analogues: May enhance the antiplatelet effect of Agents with Antiplatelet Properties. Monitor therapy

Rivaroxaban: Aspirin may enhance the adverse/toxic effect of Rivaroxaban. Specifically, the risk of bleeding may be increased. Management: Carefully consider risks and benefits of this combination and monitor closely. Consider therapy modification

Salicylates: Agents with Antiplatelet Properties may enhance the adverse/toxic effect of Salicylates. Increased risk of bleeding may result. Monitor therapy

Salicylates: May enhance the anticoagulant effect of other Salicylates. Monitor therapy

Selective Serotonin Reuptake Inhibitors: May enhance the antiplatelet effect of Aspirin. Monitor therapy

Serotonin/Norepinephrine Reuptake Inhibitors: May enhance the antiplatelet effect of Aspirin. Monitor therapy

Sulfinpyrazone: Salicylates may decrease the serum concentration of Sulfinpyrazone. Avoid combination

Talniflumate: Aspirin may enhance the adverse/toxic effect of Talniflumate. Management: When possible, consider alternatives to this combination. Concurrent use is generally not recommended. Consider therapy modification

Thrombolytic Agents: Agents with Antiplatelet Properties may enhance the anticoagulant effect of Thrombolytic Agents. Monitor therapy

Thrombolytic Agents: Salicylates may enhance the adverse/toxic effect of Thrombolytic Agents. An increased risk of bleeding may occur. Monitor therapy

Ticagrelor: Aspirin may enhance the antiplatelet effect of Ticagrelor. Aspirin may diminish the therapeutic effect of Ticagrelor. More specifically, the benefits of ticagrelor relative to clopidogrel may be diminished in adult patients receiving daily aspirin doses greater than 100-150 mg daily. Management: Avoid daily aspirin doses greater than 100 mg in adults receiving ticagrelor. Canadian recommendations are to avoid adult daily aspirin doses greater than 150 mg. Daily low-dose aspirin (U.S.: 75-100 mg; Canada: 75-150 mg) is recommended. Consider therapy modification

Tiludronate: Aspirin may decrease the serum concentration of Tiludronate. Monitor therapy

Tipranavir: May enhance the antiplatelet effect of Agents with Antiplatelet Properties. Monitor therapy

Tositumomab and Iodine I 131 Tositumomab: Agents with Antiplatelet Properties may enhance the adverse/toxic effect of Tositumomab and Iodine I 131 Tositumomab. Specifically, the risk of bleeding-related adverse events may be increased. Monitor therapy

Treprostinil: May enhance the adverse/toxic effect of Salicylates. Bleeding may occur. Monitor therapy

Urokinase: Agents with Antiplatelet Properties may enhance the anticoagulant effect of Urokinase. Avoid combination

Valproate Products: Salicylates may increase the serum concentration of Valproate Products. Monitor therapy

Varicella Virus-Containing Vaccines: Salicylates may enhance the adverse/toxic effect of Varicella Virus-Containing Vaccines. Reye's Syndrome may develop. Consider therapy modification

Vitamin E (Systemic): May enhance the antiplatelet effect of Agents with Antiplatelet Properties. Monitor therapy

Vitamin K Antagonists (eg, warfarin): Salicylates may enhance the anticoagulant effect of Vitamin K Antagonists. Consider therapy modification

Test Interactions

False-negative results for glucose oxidase urinary glucose tests (Clinistix); false-positives using the cupric sulfate method (Clinitest); also, interferes with Gerhardt test, VMA determination; 5-HIAA, xylose tolerance test and T3 and T4

Adverse Reactions

As with all drugs which may affect hemostasis, bleeding is associated with aspirin. Hemorrhage may occur at virtually any site. Risk is dependent on multiple variables including dosage, concurrent use of multiple agents which alter hemostasis, and patient susceptibility. Many adverse effects of aspirin are dose related, and are extremely rare at low dosages. Other serious reactions are idiosyncratic, related to allergy or individual sensitivity. Accurate estimation of frequencies is not possible.

Cardiovascular: Cardiac arrhythmia, edema, hypotension, tachycardia

Central nervous system: Agitation, cerebral edema, coma, confusion, dizziness, fatigue, headache, hyperthermia, insomnia, lethargy, nervousness, Reye's syndrome

Dermatologic: Skin rash, urticaria

Endocrine & metabolic: Acidosis, dehydration, hyperglycemia, hyperkalemia, hypernatremia (buffered forms), hypoglycemia (children)

Gastrointestinal: Gastrointestinal ulcer (6% to 31%), duodenal ulcer, dyspepsia, epigastric distress, gastritis, gastrointestinal erosion, heartburn, nausea, stomach pain, vomiting

Genitourinary: Postpartum hemorrhage, prolonged gestation, prolonged labor, proteinuria, stillborn infant

Hematologic & oncologic: Anemia, blood coagulation disorder, disseminated intravascular coagulation, hemolytic anemia, hemorrhage, iron deficiency anemia, prolonged prothrombin time, thrombocytopenia

Hepatic: Hepatitis (reversible), hepatotoxicity, increased serum transaminases

Hypersensitivity: Anaphylaxis, angioedema

Neuromuscular & skeletal: Acetabular bone destruction, rhabdomyolysis, weakness

Otic: Hearing loss, tinnitus

Renal: Increased blood urea nitrogen, increased serum creatinine, interstitial nephritis, renal failure (including cases caused by rhabdomyolysis), renal insufficiency, renal papillary necrosis

Respiratory: Asthma, bronchospasm, dyspnea, hyperventilation, laryngeal edema, noncardiogenic pulmonary edema, respiratory alkalosis, tachypnea

Miscellaneous: Low birth weight

Postmarketing and/or case reports (Limited to important or life-threatening): Anorectal stenosis (suppository), atrial fibrillation (toxicity), cardiac conduction disturbance (toxicity), cerebral infarction (ischemic), cholestatic jaundice, colitis, colonic ulceration, coronary artery vasospasm, delirium, esophageal obstruction, esophagitis (with esophageal ulcer), hematoma (esophageal), macular degeneration (age-related) (Li 2014), periorbital edema, rhinosinusitis

Warnings/Precautions

Concerns related to adverse effects:

• Salicylate sensitivity: Patients with sensitivity to tartrazine dyes, nasal polyps, and asthma may have an increased risk of salicylate sensitivity.

• Tinnitus: Discontinue use if tinnitus or impaired hearing occurs.

• Upper gastrointestinal (UGI) events (eg, symptomatic or complicated ulcers): Low-dose aspirin for cardioprotective effects is associated with a two- to fourfold increase in UGI events. The risks of these events increase with increasing aspirin dose; during the chronic phase of aspirin dosing, doses >81 mg are not recommended unless indicated (Bhatt, 2008).

Disease-related concerns:

• Bleeding disorders: Use with caution in patients with platelet and bleeding disorders.

• Dehydration: Use with caution in patients with dehydration.

• Ethanol use: Heavy ethanol use (>3 drinks/day) can increase bleeding risks and may enhance gastric mucosal damage.

• Gastrointestinal disease: Use with caution in patients with erosive gastritis. Avoid use in patients with active peptic ulcer disease.

• Hepatic impairment: Avoid use in severe hepatic failure.

• Renal impairment: When using high dosages (eg, analgesic or anti-inflammatory uses), use with caution and monitor renal function or consider the use of an alternative analgesic/anti-inflammatory agent (NKF [Henrich 1996], Whelton 2000). Low-dose aspirin (eg, 75 to 162 mg daily) may be safely used in patients with any degree of renal impairment (KDOQI 2005, KDOQI 2007).

Concurrent drug therapy issues:

• Alteplase: In the treatment of acute ischemic stroke, avoid aspirin for 24 hours following administration of alteplase; administration within 24 hours increases the risk of hemorrhagic transformation (Jauch, 2013).

• Clopidogrel: Concurrent use of aspirin and clopidogrel is not recommended for secondary prevention of ischemic stroke or TIA in patients unable to take oral anticoagulants due to hemorrhagic risk (Furie, 2011).

• COX-2 inhibitors/NSAIDs: When used concomitantly with ≤325 mg of aspirin, NSAIDs (including selective COX-2 inhibitors) substantially increase the risk of gastrointestinal complications (eg, ulcer); concomitant gastroprotective therapy (eg, proton pump inhibitors) is recommended (Bhatt, 2008).

• Drug-drug interactions: Potentially significant interactions may exist, requiring dose or frequency adjustment, additional monitoring, and/or selection of alternative therapy. Consult drug interactions database for more detailed information.

Special populations:

• Pediatric: When used for self-medication (OTC labeling): Children and teenagers who have or are recovering from chickenpox or flu-like symptoms should not use this product. Changes in behavior (along with nausea and vomiting) may be an early sign of Reye's syndrome; patients should be instructed to contact their healthcare provider if these occur.

• Pregnancy: In general, low doses during pregnancy needed for the treatment of certain medical conditions have not been shown to cause fetal harm; however, discontinuing therapy prior to delivery is recommended. Use of safer agents for routine management of pain or headache throughout pregnancy should be considered. If possible, avoid use during the third trimester of pregnancy.

• Surgical patients: ASA should be avoided (if possible) in surgical patients for 1 to 2 weeks prior to surgery, to reduce the risk of excessive bleeding (except in patients with cardiac stents that have not completed their full course of dual antiplatelet therapy [aspirin, clopidogrel]; patient specific situations need to be discussed with cardiologist; AHA/ACC/SCAI/ACS/ADA Science Advisory provides recommendations).

Dosage form specific issues:

• Polysorbate 80: Some dosage forms may contain polysorbate 80 (also known as Tweens). Hypersensitivity reactions, usually a delayed reaction, have been reported following exposure to pharmaceutical products containing polysorbate 80 in certain individuals (Isaksson, 2002; Lucente 2000; Shelley, 1995). Thrombocytopenia, ascites, pulmonary deterioration, and renal and hepatic failure have been reported in premature neonates after receiving parenteral products containing polysorbate 80 (Alade, 1986; CDC, 1984). See manufacturer’s labeling.

Other warnings/precautions:

• Resistance: Aspirin resistance is defined as measurable, persistent platelet activation that occurs in patients prescribed a therapeutic dose of aspirin. Clinical aspirin resistance, the recurrence of some vascular event despite a regular therapeutic dose of aspirin, is considered aspirin treatment failure. Proposed mechanisms of aspirin resistance include poor adherence with therapy, poor absorption, inadequate dosage, drug interactions, increased isoprostane activity, platelet hypersensitivity to agonists, increased COX-2 activity, COX-1 polymorphism, and platelet alloantigen 2 polymorphism of platelet glycoprotein IIIa. Estimates of biochemical aspirin resistance range from 5.5% to 60% depending on the population studied and the assays used (Gasparyan, 2008). Patients with aspirin resistance may have a higher risk of cardiovascular events compared to those who are aspirin sensitive (Gum, 2003). Aspirin resistance is likely dose-related but may be influenced by dynamic factors yet to be identified; further research is required.

Pregnancy Considerations

Salicylates have been noted to cross the placenta and enter fetal circulation. Adverse effects reported in the fetus include mortality, intrauterine growth retardation, salicylate intoxication, bleeding abnormalities, and neonatal acidosis. Use of aspirin close to delivery may cause premature closure of the ductus arteriosus. Adverse effects reported in the mother include anemia, hemorrhage, prolonged gestation, and prolonged labor (Østensen, 1998). Low-dose aspirin may be used to prevent preeclampsia in women with a history of early-onset preeclampsia and preterm delivery (<34 0/7 weeks), or preeclampsia in ≥1 prior pregnancy (ACOG, 2013). Low-dose aspirin is used to treat complications resulting from antiphospholipid syndrome in pregnancy (either primary or secondary to SLE) (ACCP [Guyatt, 2012]; Carp, 2004; Tincani, 2003). Low-dose aspirin to prevent thrombosis may also be used during the second and third trimesters in women with prosthetic valves (mechanical or bioprosthetic). The use of warfarin is recommended, along with low dose aspirin, in those with mechanical prosthetic valves (Nishimura, 2014). In general, low doses during pregnancy needed for the treatment of certain medical conditions have not been shown to cause fetal harm; however, discontinuing therapy prior to delivery is recommended (Østensen, 2006). Use of safer agents for routine management of pain or headache should be considered.

Patient Education

• Discuss specific use of drug and side effects with patient as it relates to treatment. (HCAHPS: During this hospital stay, were you given any medicine that you had not taken before? Before giving you any new medicine, how often did hospital staff tell you what the medicine was for? How often did hospital staff describe possible side effects in a way you could understand?)

• Patient may experience heartburn, vomiting, or nausea. Have patient report immediately to prescriber signs of abdominal ulcers (severe abdominal or back pain; black, tarry, or bloody stools; vomiting blood or vomit that looks like coffee grounds; or weight gain or abnormal swelling), signs of bleeding (vomiting blood or vomit that looks like coffee grounds; coughing up blood; hematuria; black, red, or tarry stools; bleeding from the gums; abnormal vaginal bleeding; bruises without a reason or that get bigger; or any severe or persistent bleeding), signs of kidney problems (urinary retention, hematuria, change in amount of urine passed, or weight gain), signs of liver problems (dark urine, fatigue, lack of appetite, nausea, abdominal pain, light-colored stools, vomiting, or jaundice), severe dizziness, passing out, confusion, severe headache, tinnitus, hearing impairment, severe abdominal pain, agitation, seizures, severe rectal pain or irritation, or rectal bleeding (HCAHPS).

• Educate patient about signs of a significant reaction (eg, wheezing; chest tightness; fever; itching; bad cough; blue skin color; seizures; or swelling of face, lips, tongue, or throat). Note: This is not a comprehensive list of all side effects. Patient should consult prescriber for additional questions.

Intended Use and Disclaimer: Should not be printed and given to patients. This information is intended to serve as a concise initial reference for health care professionals to use when discussing medications with a patient.You must ultimately rely on your own discretion, experience, and judgment in diagnosing, treating, and advising patients.

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