Dosing & Uses
Dosage Forms & Strengths
tablet
- 81mg
- 325mg
- 500mg
tablet, delayed-release
- 162mg
- 325mg
- 500mg
tablet, chewable
- 81mg
tablet, enteric-coated
- 81mg
- 162mg
- 325mg
- 650mg
extended-release capsule (Durlaza [Rx])
- 162.5 mg
Pain and Fever
Immediate release: 325- 650 mg PO q4hr PRN or 975 mg PO q6hr PRN or 500-1,000 mg PO q4-6hr for no more than 10 days; not to exceed 4 g/day
Rectal: 300-600 mg PR q4hr for no more than 10 days or as directed by health care provider
Acute Coronary Syndrome
For use as adjunctive antithrombotic effects for ACS (ST-segment elevation myocardial infarction [STEMI], unstable angina [UA]/non-ST-segment elevation myocardial infarction [NSTEMI])
Acute symptoms
- 160-325 mg PO; chew nonenteric-coated tablet upon presentation (within minutes of symptoms)
- If unable to take PO, may give 300-600 mg suppository PR
Maintenance (secondary prevention)
- 81-325 mg PO qDay indefinitely (preferred dose); may give 81-325 mg/day
- Regimen may depend on coadministered drugs or comorbid conditions
- Extended-release capsule (Durlaza [Rx]): 162.5 mg PO qDay
Percutaneous transluminal coronary angioplasty
- Adjunctive aspirin therapy to support reperfusion with primary PCI (with or without fibrinolytic therapy)
- Preprocedure: 162-325 mg PO before procedure
- Postprocedure: 81 mg PO qDay indefinitely (preferred dose) may give 81-325 mg/day
- Regimen may depend on coadministered drugs or comorbid conditions
- Coadministered with ticagrelor: 81 mg PO qDay
Primary ASCVD Prevention with Low-Dose Aspirin
Adults aged 40-70 years: Consider use of low-dose aspirin (75-100 mg PO qDay) for select adults who are at higher risk for atherosclerotic cardiovascular disease (ASCVD), but not at increased bleeding risk (AHA/ACC 2019 Guidelines on Primary Prevention of Cardiovascular Disease)
Adults aged >70 years: Low-dose aspirin should not be administered on a routine basis for primary prevention of ASCVD
Any age with increased bleeding risk: Do not administer low-dose aspirin for primary prevention
Note: There may be select circumstances where clinicians might discuss prophylactic aspirin with adults aged <40 yr or >70 yr in the context of other known ASCVD risk factors (eg, strong family history of premature MI, inability to achieve lipid or BP or glucose targets, or significant elevation in coronary artery calcium score)
Ischemic Stroke & Transient Ischemic Attack
Initial: 160-325 mg PO within 48 hr of stroke/TIA onset, followed by 75-100 mg PO qDay
AHA/ASA recommends an initial dose of 325 mg within 24-48 hr after stroke; do not administer aspirin within 24 hr after administration of alteplase
Maintenance (secondary prevention)
- Extended-release capsule (Durlaza [Rx]): 162.5 mg PO qDay
Anti-Inflammatory
Use of non-aspirin NSAIDs has largely supplanted the use of aspirin for osteoarthritis, rheumatoid arthritis, and other inflammatory arthritides
Immediate release: Usual maintenance dose: 2.1-7.3 g/day in divided doses (individualize dose); monitor serum salicylate concentrations
Colorectal Cancer (Off-label)
Prophylaxis
600 mg/day PO
Decreases risk of developing hereditary colorectal cancer (ie, Lynch syndrome) by 60% if taken daily for at least 2 years
Dosing Modifications
Renal impairment
- CrCl >10 mL/min: Dose adjustment not necessary
- CrCl <10 mL/min: Not recommended
Hepatic impairment
- Severe liver disease: Not recommended
Dosage Forms & Strengths
tablet
- 81mg
- 325mg
- 500mg
tablet, delayed release
- 162mg
- 325mg
- 500mg
tablet, chewable
- 75mg
- 81mg
tablet, enteric coated
- 81mg
- 162mg
- 325mg
- 650mg
Pain and Fever
<50 kg
- 10-15 mg/kg PO q4hr, up to 60-80 mg/kg/day
≥50 kg
- Immediate release: 325-650 mg PO/PR q4-6hr PRN; not to exceed 4 g/day
Juvenile Rheumatoid Arthritis
<25 kg: 60-100 mg/kg/day PO divided q6-8hr (maintain serum salicylate at 150-300 mcg/mL)
≥25 kg: 2.4-3.6 g/day
Kawasaki Disease
Febrile phase: 80-100 mg/kg/day PO divided q6hr for up to 14 days (48-72 hours after fever defervescence)
Maintenance: 3-6 mg/kg/day PO in single dose
Interactions
Interaction Checker
No Results

Contraindicated
Serious - Use Alternative
Significant - Monitor Closely
Minor

Adverse Effects
Frequency Not Defined
Angioedema
Bronchospasm
CNS alteration
Dermatologic problems
GI pain, ulceration, bleeding
Hepatotoxicity
Hearing loss
Nausea
Platelet aggregation inhibition
Premature hemolysis
Pulmonary edema (salicylate-induced, noncardiogenic)
Rash
Renal damage
Tinnitus
Urticaria
Vomiting
Warnings
Contraindications
Hypersensitivity to aspirin or NSAIDs; aspirin-associated hypersensitivity reactions include aspirin-induced urticaria (HLA-DRB1*1302-DQB1*0609 haplotype), aspirin-intolerant asthma (HLA-DPB1*0301)
Allergy to tartrazine dye
Absolute
- Bleeding GI ulcers, hemolytic anemia from pyruvate kinase (PK) and glucose-6-phosphate dehydrogenase (G6PD) deficiency, hemophilia, hemorrhagic diathesis, hemorrhoids, lactating mother, nasal polyps associated with asthma, sarcoidosis, thrombocytopenia, ulcerative colitis
Relative
- Appendicitis, asthma (bronchial), chronic diarrhea, bowel outlet obstruction (for enteric-coated formulations), dehydration, erosive gastritis, hypoparathyroidism
Cautions
Anemia, GI malabsorption, history of peptic ulcers, gout, hepatic disease, hypochlorhydria, hypoprothrombinemia, renal impairment, thyrotoxicosis, vitamin K deficiency, renal calculi, ethanol use (may increase bleeding)
Discontinue therapy if tinnitus develops
Should be taken with food or 8-12 oz of water to avoid GI effects
Not indicated for children with viral illness; use of salicylates in pediatric patients with varicella or influenzalike illness is associated with increased incidence of Reye syndrome
Heart Failure (HF) risk
- NSAIDS have the potential to trigger HF by prostaglandin inhibition that leads to sodium and water retention, increased systemic vascular resistance, and blunted response to diuretics
- High-dose aspirin (greater than 325mg) should be avoided or withdrawn whenever possible
- AHA/ACC Heart Failure Guidelines; Circulation. 2016; 134
Pregnancy & Lactation
Pregancy
Avoid chronic or intermittent high doses during pregnancy; may affect maternal and newborn hemostasis mechanisms, leading to an increased risk of hemorrhage
High doses may also increase perinatal mortality by intrauterine growth restriction and teratogenic effects
Near term, aspirin may prolong gestation and labor
Premature closure of the ductus arteriosus may occur if used near term with use of full-dose aspirin
Seek advice of health professional before using OTC drugs during pregnancy
Lactation
Drug enters breast milk; a decision should be made regarding whether to discontinue nursing or to discontinue drug, taking into account importance of drug to mother
Seek advice of health professional before using OTC drugs while breastfeeding
Pregnancy Categories
A: Generally acceptable. Controlled studies in pregnant women show no evidence of fetal risk.
B: May be acceptable. Either animal studies show no risk but human studies not available or animal studies showed minor risks and human studies done and showed no risk. C: Use with caution if benefits outweigh risks. Animal studies show risk and human studies not available or neither animal nor human studies done. D: Use in LIFE-THREATENING emergencies when no safer drug available. Positive evidence of human fetal risk. X: Do not use in pregnancy. Risks involved outweigh potential benefits. Safer alternatives exist. NA: Information not available.Pharmacology
Mechanism of Action
Inhibits synthesis of prostaglandin by cyclooxygenase; inhibits platelet aggregation; has antipyretic and analgesic activity
Absorption
Bioavailability: 80-100%
Onset: PO, 5-30 min; PR, 1-2 hr
Duration: PO, 4-6 hr; PR, >7 hr
Peak plasma time: PO, 0.25-3 hr
Peak plasma concentration: Analgesia/antipyresis, 30-100 mcg/mL; anti-inflammatory, 150-300 mcg/mL
Distribution
Protein bound: ≤100 mcg/mL, 90-95%; 100-400 mcg/mL, 70-85%; higher concentrations, 25-60%
Vd: 170 mL/kg
Metabolism
Metabolized by liver via microsomal enzyme system
Metabolites: Salicylurate, salicyl phenolic glucuronide, salicyl acyl glucuronide, 2,5-dihydroxybenzoic acid (gentisic acid), 2,3-dihydroxybenzoic acid, 2,3,5-trihydroxybenzoic acid, gentisuric acid (active)
Enzymes inhibited: Cyclooxygenase (insignificant)
Elimination
Half-life: Low dose, 2-3 hr; higher dose, 15-30 hr
Renal clearance: 80-100% in 24-72 hr
Excretion: Urine (80-100%), sweat, saliva, feces
Dialyzable: Yes
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Formulary
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