Standard Dose for Pain or Fever Relief
Adults typically take 325-650 mg of aspirin every 4-6 hours as needed, not exceeding 4 grams per day. This applies to immediate-release formulations for short-term use.[1][2]
Low-Dose for Heart Attack Prevention
For cardiovascular protection, the common dose is 81 mg (often called 'baby aspirin') once daily. Higher doses like 162-325 mg may be used short-term after a heart event, under medical guidance.[1][3]
Dosing for Stroke Prevention
81 mg daily reduces risk of ischemic stroke in at-risk adults. Some guidelines recommend 75-162 mg for secondary prevention after a transient ischemic attack.[2][4]
Factors Affecting Dose
Age, weight, kidney function, and bleeding risk adjust dosing. People over 60 or with ulcers often start at lower doses to minimize gastrointestinal bleeding. Always take with food or water.[1][5]
What Happens If You Take Too Much
Overdose risks include stomach bleeding, tinnitus, or severe poisoning above 4 grams daily. Symptoms start at 150 mg/kg body weight; seek emergency care immediately.2
Aspirin vs. Ibuprofen or Acetaminophen
Aspirin irreversibly blocks platelets for heart benefits, unlike ibuprofen (reversible) or acetaminophen (no platelet effect). Switch if allergic or for non-heart pain.[3][4]
Who Should Avoid or Adjust Aspirin
Avoid if history of ulcers, asthma triggered by NSAIDs, or concurrent blood thinners. Children under 16 skip it due to Reye's syndrome risk. Consult a doctor for pregnancy or breastfeeding.[1][5]
[1]: https://www.mayoclinic.org/drugs-supplements/aspirin-oral-route-rectal-route/proper-use/drg-20152665
[2]: https://medlineplus.gov/druginfo/meds/a601040.html
[3]: https://www.heart.org/en/health-topics/heart-attack/treatment-of-a-heart-attack/aspirin-and-heart-disease
[4]: https://www.aha.org/aha-guidelines/aspirin-stroke-prevention
[5]: https://www.fda.gov/drugs/postmarket-drug-safety-information-patients-and-providers/aspirin-know-facts