POLL: Aspirin Therapy

[Momto3]

I was recently started on aspirin therapy and because this is so new to me, I am wondering how many others are taking an aspirin.  If so, what dose have you been prescribed?  I'm on one 325mg coated aspirin/day.

Thanks all!'

Connie

[kenkeith]

I have to say bluntly disagree, and  I say vociferously I have not read anything (numerous reads over 4 years) from any reputed source or study that even implies the number of risk factors is a criterion for dosage.

Two or three risk factors...dose 325mg.  Age is a risk factor as is history of occlusion.  So everyone over the age of 45? , whatever, and a history with a stent implant should be on 325mg.!!

Included is a factor there should be no history of bleeding.  There may not be any history of bleeding until dosed with 4325mg!  There are lab tests that time clotting, and a higher dose than a predictable range of efficacy for a specific individual should be the critereon.  

[ChatterAlly]

Thank you so much for the information. It sure helps to understand. And thanks to all the drs here that take the time to keep us informed. What a great reassurance.

Ally

[Momto3]

Thanks for the great information.......I'm somewhat stumped as to why I'm taking the higher dose.....and I sure don't want to end up with gastrointestinal bleeding!

[Momto3]

Thank you so much for the meta-analyses summary!!  Going from one single study to another is mind-boggling.  

So, I'm thinking that until a PFO and/or embolic problems are ruled out, I may be better off with the higher dose.  I have low cholesterol, good ratio, low triglycerides, normal glucose, low-normal BP, non smoker, but I do have family history for CAD.  Think I'm OK there.  But,what would you say are the risk factors for stroke?  What started this was a temporary, partial loss of vision in one eye (like a black splotch in my field of vision) - normal eye exam, history of MVP/MR, history of opthalmic migraines generally lasting about 20 minutes (jagged lines, flashing, shimmering).

Thanks again for the great summary!  I feel better with some clarification.

Connie    

[kenkeith]

Although pharmacodynamic data demonstrate that long-term aspirin dosages as low as 30 mg/d are adequate to fully inhibit platelet thromboxane production, dosages as high as 1300 mg/d are approved for use. In the United States, 81 mg/d of aspirin is prescribed most commonly (60%), followed by 325 mg/d (35%). The available evidence, predominantly from secondary-prevention observational studies, supports that dosages greater than 75 to 81 mg/d do not enhance efficacy, whereas larger dosages are associated with an increased incidence of bleeding events, primarily related to gastrointestinal tract toxicity.

Currently available clinical data do not support the routine, long-term use of aspirin dosages greater than 75 to 81 mg/d in the setting of cardiovascular disease prevention. Higher dosages, which may be commonly prescribed, do not better prevent events but are associated with increased risks of gastrointestinal bleeding.

If is someone is over weight, a larger does may be indicated?.  There is no reliable  evidence that supports a higher dose than 81 mg for thrombosis prevention or thromboartritis (clotting with inflammation).

[Lee Kirksey, MD]

Great Question

50 Million People Take Aspirin for CVD Prevention in United States Alone
In the current review, Campbell and colleagues note that approximately 36% of the adult US population — more than 50 million people — are estimated to take aspirin regularly for heart disease prevention. This translates into roughly 10 to 20 billion aspirin tablets consumed annually in the United States alone. The authors stress that, as aspirin is so widely used, maximizing benefits and minimizing risks by providing optimal dosing is of great importance. They note that clinical trials in patients with heart disease have evaluated dosages as low as 30 mg/day and as high as 1500 mg/day, and the US Food and Drug Administration recommends dosages ranging from 50 to 1300 mg/day for treatment of the clinical manifestations of atherosclerotic disease. Because of this, there is substantial debate regarding what represents the "correct" dosage of aspirin and whether it is the same in all patients.

The authors therefore conducted a systematic review of the literature of prospective studies using different aspirin dosages in the setting of cardiovascular disease (CVD). A total of 2415 references were identified and manually sorted using the abstracts or full-text publications.

The authors report that clinical outcomes trials directly comparing different dosages of aspirin (from 30 - 1300 mg/day) in almost 10,000 patients with various clinical manifestations of atherosclerotic disease have not shown a significant benefit of higher dosages, and in most trials, the lowest event rates were seen among patients randomized to the low-dosage groups.

The authors also point out that several meta-analyses have shown similar results. One meta-analysis of 11 clinical trials including 5228 patients randomized to aspirin or placebo following a transient ischemic attack or stroke, found similar efficacy for aspirin dosages ranging from 50 to 1500 mg/day. And in the Antithrombotic Trialists' Collaboration, a meta-analysis of more than 60 aspirin trials also found no relationship between dose and efficacy, with the greatest risk reduction shown in trials using a 75- to 150-mg dose of aspirin. The authors add that retrospective analyses of several recent large-scale clinical trials (including Global Use of Strategies to Open Occluded Arteries [GUSTO] IIb, Platelet Glycoprotein IIb/IIIa in Unstable Angina: Receptor Antagonism Using Integrilin Therapy [PURSUIT], and Clopidogrel in Unstable Angina to Prevent Recurrent Events [CURE]) are also consistent with the lack of any increase in benefit with higher dosages of aspirin.

But in contrast to the efficacy data, larger doses of aspirin are associated with an increased incidence of bleeding events, primarily related to gastrointestinal tract toxicity. Campbell and colleagues note that if the differences in major bleeding found in the aspirin-only group of the CURE trial are translated to the general US aspirin-taking population, daily treatment with 325 mg of aspirin would lead to an excess of more than 900,000 major bleeding events per year compared with a daily dose of 81 mg.

My Summary: I believe that everyone should be on aspirin daily. The benefits are clear in reduction of heart attack and stroke and even in the reduction of colon polyps. The optimal dose is unclear. For patients at low risk for stroke or heart attack, I recommend 81 mg/day. For patients with 2-3 risk factors and no history of bleeding, I recommend 325 mg/day,