Editing Aspirin (section)

== Dosages ==

Adult aspirin tablets are produced in standardised sizes, which vary slightly from country to country, for example 300{{nbsp}}mg in Britain and 325{{nbsp}}mg in the United States. Smaller doses are based on these standards, ''e.g.'', 75{{nbsp}}mg and 81{{nbsp}}mg tablets. The 81&nbsp;mg tablets are commonly called "baby aspirin" or "baby-strength", because they were originally{{snd}}[[Reye syndrome|but no longer]]{{snd}}intended to be administered to infants and children.<ref>{{cite web |title = Invention of the safety cap |url = http://digitaldukemed.mc.duke.edu/pcc/safety_cap.html |website = digitaldukemed.mc.duke.edu |access-date = 4 September 2015 |url-status = live |archive-url = https://web.archive.org/web/20160304071131/http://digitaldukemed.mc.duke.edu/pcc/safety_cap.html |archive-date = 4 March 2016}}</ref> No medical significance occurs due to the slight difference in dosage between the 75{{nbsp}}mg and the 81{{nbsp}}mg tablets. The dose required for benefit appears to depend on a person's weight.<ref name="Lancet2018Dose">{{cite journal | vauthors = Rothwell PM, Cook NR, Gaziano JM, Price JF, Belch JF, Roncaglioni MC, Morimoto T, Mehta Z | title = Effects of aspirin on risks of vascular events and cancer according to bodyweight and dose: analysis of individual patient data from randomised trials | journal = Lancet | volume = 392 | issue = 10145 | pages = 387–399 | date = August 2018 | pmid = 30017552 | pmc = 6083400 | doi = 10.1016/S0140-6736(18)31133-4 }}</ref> For those weighing less than {{convert|70|kg|lb|0}}, low dose is effective for preventing cardiovascular disease; for patients above this weight, higher doses are required.<ref name=Lancet2018Dose/>

In general, for adults, doses are taken four times a day for fever or arthritis,<ref name=BNF>{{cite book|title=British National Formulary|edition=45|year=2003|publisher= [[British Medical Journal]] and [[Royal Pharmaceutical Society of Great Britain]]|title-link=British National Formulary}}</ref> with doses near the maximal daily dose used historically for the treatment of [[rheumatic fever]].<ref>{{cite web |url=http://www.medscape.com/druginfo/monograph?cid=med&drugid=3881&drugname=Aspirin+EC+Oral&monotype=monograph |title=Aspirin monograph: dosages, etc |publisher=Medscape.com |access-date=11 May 2011}}</ref> For the prevention of [[myocardial infarction]] (MI) in someone with documented or suspected [[coronary artery disease]], much lower doses are taken once daily.<ref name=BNF />

March 2009 recommendations from the USPSTF on the use of aspirin for the primary prevention of coronary heart disease encourage men aged 45–79 and women aged 55–79 to use aspirin when the potential benefit of a reduction in MI for men or stroke for women outweighs the potential harm of an increase in [[Gastrointestinal bleeding|gastrointestinal hemorrhage]].<ref name="USPSTF 2009">{{cite journal | vauthors = ((US Preventive Services Task Force)) | title = Aspirin for the prevention of cardiovascular disease: U.S. Preventive Services Task Force recommendation statement | journal = Annals of Internal Medicine | volume = 150 | issue = 6 | pages = 396–404 | date = March 2009 | pmid = 19293072 | doi = 10.7326/0003-4819-150-6-200903170-00008 | doi-access = free | title-link = doi }}</ref><ref name=medscape>{{cite news|url=http://cme.medscape.com/viewarticle/589895 |title=Aspirin: more evidence that low dose is all that is needed |newspaper=Medscape |publisher=Medscape CME |access-date=11 May 2011}}</ref>{{update inline|date=October 2019}} The WHI study of postmenopausal women found that aspirin resulted in a 25% lower risk of death from cardiovascular disease and a 14% lower risk of death from any cause, though there was no significant difference between 81{{nbsp}}mg and 325{{nbsp}}mg aspirin doses.<ref>{{cite journal | vauthors = Berger JS, Brown DL, Burke GL, Oberman A, Kostis JB, Langer RD, Wong ND, Wassertheil-Smoller S |date=March 2009 |title=Aspirin Use, Dose, and Clinical Outcomes in Postmenopausal Women With Stable Cardiovascular Disease |journal=Circulation: Cardiovascular Quality and Outcomes |volume=2 |issue=2 |pages=78–87 |doi=10.1161/circoutcomes.108.791269 |pmid=20031819 |pmc=2801891 |issn=1941-7713 }}</ref> The 2021 ADAPTABLE study also showed no significant difference in cardiovascular events or major bleeding between 81{{nbsp}}mg and 325{{nbsp}}mg doses of aspirin in patients (both men and women) with established cardiovascular disease.<ref>{{cite journal | vauthors = Sacristán JA |date=August 2021 |title=Aspirin Dosing in Cardiovascular Disease |journal=New England Journal of Medicine |volume=385 |issue=8 |pages=764–765 |doi=10.1056/nejmc2110476 |pmid=34407352 |s2cid=237214969 |issn=0028-4793 }}</ref>

Low-dose aspirin use was also associated with a trend toward lower risk of cardiovascular events, and lower aspirin doses (75 or 81{{nbsp}}mg/day) may optimize efficacy and safety for people requiring aspirin for long-term prevention.<ref name="medscape" />

In children with Kawasaki disease, aspirin is taken at dosages based on body weight, initially four times a day for up to two weeks and then at a lower dose once daily for a further six to eight weeks.<ref>{{cite book|title=British National Formulary for Children|year=2006|publisher= [[British Medical Journal]] and [[Royal Pharmaceutical Society]]|title-link=British National Formulary for Children}}</ref>