Hello Paul,
Aspirin can reduce the risk of a heart attack or stroke if taken
regularly on a long-term basis. Ibuprofen can block this protective
effect of aspirin. Acetaminophen does not appear to have any positive
or negative effect on these matters.
Daily use of aspirin has been shown to prevent the formation of blood
clots which can cause a heart attack or stroke. This effect of
aspirin is due to the fact that it inhibits an enzyme called
cyclooxygenase-1 (often referred to as COX-1). When this enzyme is
inhibited, levels of a substance called thromboxane A2 decrease. As a
result, the platelets in the blood are less likely to clump together
and start the formation of a clot.
In December last year, an article was published, which showed that
ibuprofen, if taken before aspirin, blocks this inhibitory action, and
therefore decreases the overall protection against clotting. When
ibuprofen was taken after aspirin, this did not happen. Acetaminophen
did not have an effect either way on anti-clotting activity.
(Catella-Lawson F, Reilly MP, Kapoor SC, Cucchiarra AJ, DeMarco S,
Tournier B, and others. Cyclooxygenase inhibitors and the antiplatelet
effects of aspirin. New England Journal of Medicine 2001 December 20;
Volume 345(no. 25): pp1809-1816.)
Thus, current advice is that someone who takes aspirin daily for its
protective effect can use ibuprofen if needed, but it should be taken
not less than four hours after the aspirin.
Information from:
“Can ibuprofen affect the blood thinning qualities of aspirin?”
University of Illinois at Chicago College of Pharmacy
http://www.uic.edu/pharmacy/services/di/ibuprofen.htm
“Can Ibuprofen Block Aspirin?” Ask My Doctor
http://www.askmydoctor.cc/health_news.asp
On the other hand, regular use of ibuprofen, but not aspirin or
acetaminophen, could protect against the development of Alzheimer
disease, according to a paper published in 1997 (Stewart WF, Kawas C,
Corrada M, Metter EJ. Risk of Alzheimer's disease and duration of
NSAID use. Neurology. 1997 March; Volume 48: pp626-632.)
Information from:
“NSAIDs but not aspirin or acetaminophen reduced the risk for
Alzheimer disease” ACP (American College of Physicians) Journal Club
http://www.acpjc.org/Content/127/2/ISSUE/ACPJC-1997-127-2-046.htm |
Clarification of Answer by
tehuti-ga
on
09 Dec 2002 07:20 PST
The only one of these three which has proven efficacy in long-term
prophylaxis against heart disease is aspirin.
Ibuprofen was found to have no protective effect in the following
study:
Lancet 2002 Jan 12;359(9301):118-123
Non-steroidal anti-inflammatory drugs and risk of serious coronary
heart disease: an observational cohort study.
Ray WA, Stein CM, Hall K, Daugherty JR, Griffin MR.
Department of Preventive Medicine, Vanderbilt University School of
Medicine, Nashville, TN 37232, USA.
"Non-aspirin, non-steroidal anti-inflammatory drugs (NANSAIDs) have
complex effects that could either prevent or promote coronary heart
disease... Absence of a protective effect of naproxen or other
NANSAIDs [including ibuprofen] on risk of coronary heart disease
suggests that these drugs should not be used for cardioprotection."
and this one:
Epidemiology 2000 Jul;11(4):382-387
Differential effects of aspirin and non-aspirin nonsteroidal
antiinflammatory drugs in the primary prevention of myocardial
infarction in postmenopausal women.
Garcia Rodriguez LA, Varas C, Patrono C.
Centro Espanol de Investigacion Farmacoepidemiologica (CEIFE), Madrid,
Spain.
"The antiplatelet effect of aspirin reduces the risk of clinical
manifestations of atherothrombosis by approximately 25% in secondary
prevention settings. Data are limited in primary prevention of
coronary heart disease, and even more in women. Here, we estimate the
effects of aspirin and non-aspirin nonsteroidal antiinflammatory drugs
in the primary prevention of myocardial infarction in postmenopausal
women. We followed a cohort of 164,769 women, 50-74 years of age...
findings indicate that incomplete and reversible inhibition of
platelet cyclooxygenase by non-aspirin nonsteroidal antiinflammatory
drugs is not sufficient to produce clinically detectable
cardiovascular protection comparable with that achieved by low-dose
aspirin through irreversible inactivation of platelet cyclooxygenase."
As I mentioned in my answer, recent research has shown that ibuprofen
can actually block the protective effect of aspirin if taken before
the aspirin.
The only reference to acetaminophen having a cardioprotective effect
that I found was a study in isolated guine pig hearts which showed it
could have an effect in protecting the extent of tissue damage
following myocardial ischemia (when the supply of blood is cut off to
part of the heart tissue). This is due to its antioxidant properties,
which counter the free radicals produced as a result of the injury.
Am J Physiol Heart Circ Physiol 2001 Jun;280(6):H2631-638
Coronary and myocardial effects of acetaminophen: protection during
ischemia-reperfusion.
Merrill G, McConnell P, Vandyke K, Powell S.
Department of Cell Biology and Neuroscience, Rutgers University,
Piscataway, New Jersey 08854-8082, USA
"Our results show that acetaminophen provides significant functional
and structural protection to the ischemic-reperfused myocardium, and
the mechanism of cardioprotection seems to involve attenuation of the
production of both hydroxyl radicals and peroxynitrite."
However, this mechanism would kick in only after a heart attack. It
would not prevent the development of a heart attack or stroke by
preventing the clots which cause it. Therefore, acetaminophen is not
effective in long-term prophylaxis in the same way as aspirin.
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