aspirin

Absorption: Well absorbed from the upper small intestine; absorption from enteric-coated preparations may be unreliable; rectal absorption is slow and variable.

Distribution: Rapidly and widely distributed; crosses the placenta and enters breast milk.

Metabolism/Excretion: Extensively metabolized by the liver; inactive metabolites excreted by the kidneys. Amount excreted unchanged by the kidneys depends on urine pH; as pH increases, amount excreted unchanged increases from 2–3% up to 80%.

Half-Life: 2–3 hr for low doses; up to 15–30 hr with larger doses because of saturation of liver metabolism.

Time/Action Profile ⬆ ⬇

(analgesia/fever reduction)

ROUTE	ONSET	PEAK	DURATION
PO	5–30 min	1–3 hr	3–6 hr

Contraind./Precautions ⬆ ⬇

Contraindicated in:

Hypersensitivity to aspirin or other salicylates;
Cross-sensitivity with other NSAIDs may exist (less with nonaspirin salicylates);
Bleeding disorders or thrombocytopenia;
OB: Avoid use after 30 wk gestation;
Pedi: May risk of Reye’s syndrome in children or adolescents with viral infections.

Use Cautiously in:

History of GI bleeding or ulcer disease;
Chronic alcohol use/abuse;
Severe hepatic or renal disease;
OB: Use at or after 20 wk gestation may cause fetal or neonatal renal impairment; if NSAID treatment is necessary between 20 wk and 30 wk gestation, limit use to the lowest effective dose and shortest duration possible;
Lactation: Safety not established in breastfeeding;
Geri: Appears on Beers list. risk of major bleeding in older adults. Avoid use for primary prevention of cardiovascular disease in older adults. Avoid chronic use for pain (at doses >325 mg/day) in older adults unless other alternatives are not effective and the patient can take a gastroprotective agent; avoid short-term use for pain (at doses >325 mg/day) in older adults in combination with oral or parenteral corticosteroids, anticoagulants, or antiplatelet agents unless other alternatives are not effective and the patient can take a gastroprotective agent.

Adv. Reactions/Side Effects ⬆ ⬇

Derm: DRUG REACTION WITH EOSINOPHILIA AND SYSTEMIC SYMPTOMS (DRESS), rash, urticaria

EENT: tinnitus

GI: dyspepsia, epigastric distress, nausea, abdominal pain, anorexia, GI BLEEDING, hepatotoxicity, vomiting

Hemat: anemia, hemolysis

Misc: HYPERSENSITIVITY REACTIONS (INCLUDING ANAPHYLAXIS AND LARYNGEAL EDEMA)

Interactions ⬆ ⬇

Drug-drug:

May ↑ the risk of bleeding with warfarin, heparin, heparin-like agents, thrombolytic agents, dipyridamole, clopidogrel, tirofiban, or eptifibatide, although these agents are frequently used safely in combination and in sequence.
Ibuprofen: may negate the cardioprotective antiplatelet effects of low-dose aspirin.
May ↑ risk of bleeding with cefotetan and valproic acid.
May ↑ activity of penicillins, phenytoin, methotrexate, valproic acid, oral hypoglycemic agents, and sulfonamides.
Urinary acidification↑ reabsorption and may ↑ serum salicylate levels.
Alkalinization of the urine or the ingestion of large amounts of antacids↑ excretion and ↓ serum salicylate levels.
May blunt the therapeutic response to diuretics and ACE inhibitors.
↑risk of GI irritation with NSAIDs.

Drug-Natural Products:

↑anticoagulant effect and bleeding risk with arnica, chamomile, clove, feverfew, garlic, ginger, ginkgo, Panax ginseng, and others.

Foods capable of acidifying the urine (see Food Sources for Specific Nutrients) may ↑ serum salicylate levels.

Route/Dosage ⬆ ⬇

Pain/Fever

PO
(Adults ): 325–1000 mg every 4–6 hr (not to exceed 4 g/day). Extended-release tablets: 650 mg every 8 hr or 800 mg every 12 hr.
PO
(Children 2–11 yr): 10–15 mg/kg/dose every 4–6 hr; maximum dose: 4 g/day.

Inflammation

PO (Adults ): 2.4 g/day initially; ↑ to maintenance dose of 3.6–5.4 g/day in divided doses (up to 7.8 g/day for acute rheumatic fever).
PO (Children ): 60–100 mg/kg/day in divided doses (up to 130 mg/kg/day for acute rheumatic fever).

Prevention of Transient Ischemic Attacks

PO (Adults ): 50–325 mg once daily.

Prevention of Myocardial Infarction/Antiplatelet Effects

PO (Adults ): 80–325 mg once daily. Suspected acute MI: 160 mg as soon as MI is suspected.
PO (Children ): 3–10 mg/kg/day given once daily (round dose to a convenient amount).

Kawasaki Disease

PO (Children ): 80–100 mg/kg/day in 4 divided doses until fever resolves; may be followed by maintenance dose of 3–5 mg/kg/day as a single dose for up to 8 wk.

Availability ⬆ ⬇

(Generic available)

Immediate-release tablets: 81 mg^OTC; 162.5 mg^OTC; 325 mg^OTC; 500 mg^OTC; 650 mg^OTC; 975 mg^OTC
Immediate-release capsules: 325 mg^OTC
Extended-release tablets: 325 mg^OTC; 650 mg^OTC; 800 mg
Enteric-coated (delayed-release) tablets: 80 mg^OTC; 165 mg^OTC; 300 mg^OTC; 325 mg^OTC; 500 mg^OTC; 600 mg^OTC; 650 mg^OTC; 975 mg^OTC
Delayed-release capsules: 325 mg^OTC; 500 mg^OTC
Chewable tablets: 80 mg^OTC; 81 mg^OTC
Dispersible tablets: 325 mg^OTC; 500 mg^OTC
Suppositories: 60 mg^OTC; 120 mg^OTC; 125 mg^OTC; 130 mg^OTC; 150 mg^OTC; 160 mg^OTC; 195 mg^OTC; 200 mg^OTC; 300 mg^OTC; 320 mg^OTC; 325 mg^OTC; 600 mg^OTC; 640 mg^OTC; 650 mg^OTC; 1.2 g^OTC
In combination with: antihistamines, decongestants, cough suppressantsOTC, and opioids. See Appendix [not included in this PDA edition].

Assessment ⬆ ⬇

Patients who have asthma, allergies, and nasal polyps or who are allergic to tartrazine are at an increased risk for developing hypersensitivity reactions.
Monitor for signs and symptoms of DRESS (fever, rash, lymphadenopathy, facial swelling) periodically during therapy. Discontinue therapy if symptoms occur.
Pain: Assess pain and limitation of movement; note type, location, and intensity before and 60 min after administration.
Fever: Assess fever and note associated signs (diaphoresis, tachycardia, malaise, chills).

Lab Test Considerations:

Monitor hepatic function before antirheumatic therapy and if symptoms of hepatotoxicity occur; more likely in patients, especially children, with rheumatic fever, systemic lupus erythematosus, juvenile arthritis, or pre-existing hepatic disease. May cause ↑ serum AST, ALT, and alkaline phosphatase, especially when plasma concentrations exceed 25 mg/100 mL. May return to normal despite continued use or dose reduction. If severe abnormalities or active liver disease occurs, discontinue and use with caution in future.
- Monitor serum salicylate levels periodically with prolonged high-dose therapy to determine dose, safety, and efficacy, especially in children with Kawasaki disease.
- May alter results of serum uric acid, urine vanillylmandelic acid (VMA), protirelin-induced thyroid-stimulating hormone (TSH), urine hydroxyindoleacetic acid (5-HIAA) determinations, and radionuclide thyroid imaging.
- Prolongs bleeding time for 4–7 days and, in large doses, may cause prolonged prothrombin time. Monitor hematocrit periodically in prolonged high-dose therapy to assess for GI blood loss.

Toxicity and Overdose:

Monitor for the onset of tinnitus, headache, hyperventilation, agitation, mental confusion, lethargy, diarrhea, and sweating. If these symptoms appear, withhold medication and notify health care professional immediately.

Implementation ⬆ ⬇

Use lowest effective dose for shortest period of time.
PO: Administer after meals or with food or an antacid to minimize gastric irritation. Food slows but does not alter the total amount absorbed.
- DNC: Do not crush or chew enteric-coated tablets. Do not take antacids within 1–2 hr of enteric-coated tablets. Chewable tablets may be chewed, dissolved in liquid, or swallowed whole. Some extended-release tablets may be broken or crumbled but must not be ground up before swallowing. See manufacturer’s prescribing information for individual products.

Patient/Family Teaching ⬆ ⬇

Instruct patient to take aspirin with a full glass of water and to remain in an upright position for 15–30 min after administration.
- Advise patient to report tinnitus; unusual bleeding of gums; bruising; black, tarry stools; or fever lasting longer than 3 days.
- Caution patient to avoid concurrent use of alcohol with this medication to minimize possible gastric irritation; 3 or more glasses of alcohol per day may increase risk of GI bleeding. Caution patient to avoid taking concurrently with acetaminophen or NSAIDs for more than a few days, unless directed by health care professional to prevent analgesic nephropathy.
- Instruct patients on a sodium-restricted diet to avoid effervescent tablets or buffered-aspirin preparations.
- Tablets with an acetic (vinegar-like) odor should be discarded.
- Advise patients on long-term therapy to inform health care professional of medication regimen before surgery. Aspirin may need to be withheld for 1 wk before surgery.
- May cause fetal harm. Advise females of reproductive potential to notify health care professional if pregnancy is planned or suspected or if breastfeeding. Advise women to avoid aspirin in the 3rd trimester of pregnancy (after 29 wk), may cause premature closure of the fetal ductus arteriosus. Use of aspirin after 20 wk may cause fetal renal dysfunction leading to oligohydramnios. May cause reversible infertility in women attempting to conceive; may consider discontinuing aspirin.
- Centers for Disease Control and Prevention warns against giving aspirin to children or adolescents with varicella (chickenpox) or influenza-like or viral illnesses because of a possible association with Reye’s syndrome.
Transient Ischemic Attacks or MI: Advise patients receiving aspirin prophylactically to take only prescribed dose. Increasing dose has not been found to provide additional benefits.

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Pronunciation ⬇

Classifications ⬆ ⬇

Indications ⬆ ⬇

Action ⬆ ⬇

Pharmacokinetics ⬆ ⬇