aspirin (acetylsalicylic acid, Bayer, Ecotrin, and others) (cont.)

Pharmacy Author:
Medical and Pharmacy Editor:

DOSING: Aspirin should be taken with food. Doses range from 50 mg to 6000 mg daily depending on the use.

  • Usual doses for mild to moderate pain are 350 or 650 mg every 4 hours or 500 mg every 6 hours.
  • Doses for rheumatoid arthritis include 500 mg every 4-6 hours; 650 mg every 4 hours; 1000 mg every 4-6 hours; 1950 mg twice daily.
  • Heart attacks are prevented with 75, 81, 162 or 325 mg daily.
  • 160 to 325 mg of non-enteric coated aspirin should be chewed immediately when experiencing symptoms of a heart attack.
  • The dose for preventing another stroke is 75 to 100 mg daily.

DRUG INTERACTIONS: Aspirin is associated with several suspected or probable interactions that affect the action of other drugs. The following examples are the most common of the suspected interactions.

NSAIDs may increase the blood levels of lithium (Eskalith, Lithobid) by reducing the excretion of lithium by the kidneys. Increased levels of lithium may lead to lithium toxicity.

Aspirin may reduce the blood pressure lowering effects of blood pressure medications. This may occur because prostaglandins have a role in the regulation of blood pressure.

When aspirin is used in combination with methotrexate (Rheumatrex, Trexall) or aminoglycoside antibiotics (for example, gentamicin) the blood levels of the methotrexate or aminoglycoside may increase, presumably because their elimination from the body is reduced. This may lead to more methotrexate or aminoglycoside-related side effects.

Individuals taking oral blood thinners or anticoagulants, for example, warfarin, (Coumadin) should avoid aspirin because aspirin also thins the blood, and excessive blood thinning may lead to serious bleeding.

PREGNANCY: Aspirin is generally avoided during pregnancy because it may adversely effect the fetus. However, low aspirin doses have been safely used for the prevention of complications of pregnancy.

NURSING MOTHERS: Aspirin is excreted into breast milk and may cause adverse effects in the infant.

Reference: FDA Drug Information

Medically Reviewed by a Doctor on 7/30/2015

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