Does Aspirin Lower Blood Pressure?
Most people know that low dose aspirin is often prescribed for
those prone to heart attack or stroke, but can aspirin also lower high blood pressure? The answer appears to be a
qualified yes. According to a 2008 study, a low dose aspirin taken daily at bedtime was associated with significant
24-hour reductions in blood pressure in a study of adults with prehypertension, which is blood pressure readings between 120/80 and
Aspirin works by interfering with your blood's clotting action.
When you bleed, your blood's clotting cells, called platelets, build up at the site of your wound. The platelets
help form a plug that seals the opening in your blood vessel to stop bleeding.
The 2008 Spanish study was
conducted by the University of Vigo’s Dr. Ramon C. Hermida. In the study, 244 adults with a median age of 43 an
a diagnosis of prehypertension were divided into three groups. Of the participants, 138 were women and 106 were
men. All of the groups participated in lifestyle intervention measures (diet and exercise counseling) throughout
the study. One group relied on lifestyle intervention alone, the second group received 100 milligrams (mg) of
aspirin in the morning, and the last group received the same aspirin dose at bedtime.
The study participants were monitored with an ambulatory device to measure blood
pressure before treatment and after three months of treatment. The monitoring device measured heart rate every
20 minutes from 7 am to 11 pm and every 30 minutes during nighttime hours for 48 hours. The group receiving
the night time dosage had systolic pressure drop more than 5 points and diastolic pressure fall by more than 3
points. The other two groups had no noticeable change. Why the aspirin therapy proved more effective at night
was not clear to the researchers, but aspirin can slow the production of hormones in the body that cause
clotting, many of which are produced while the body is at rest.
Although these results are very positive and demonstrate that
aspirin may help control early stage high blood pressure, this is still a small study and aspirin is not a miracle
cure. Many people have an allergic reaction to aspirin, and others may experience bleeding, stomach pain, or a
rapid heartbeat. Consult your doctor before attempting any aspirin therapy to reduce your blood pressure. Aspirin
does lower blood pressure and if you are interested in learning more about its benefits and
risks, more information can be found at the US National Library of Medicine.
Cautions for Daily Aspirin Therapy
You shouldn't take a daily aspirin if you have health conditions
that could increase your risk of bleeding or other complications. These conditions include:
- A bleeding or clotting disorder (bleeding easily)
- Stomach ulcers
- Heart failure
It is important to tell your doctor what other medications or
supplements you might be taking, even if it's just ibuprofen (Advil, Motrin, others). Taking aspirin and ibuprofen
together reduces the beneficial effects of the aspirin. Taking aspirin with other anticoagulants, such as warfarin
(Coumadin), could greatly increase your chance of bleeding.
Although a 100 mg dose of aspirin was used in the study, there is
no standardized dose you should take to get the benefits of daily aspirin therapy. You and your doctor should
discuss what dosage is right for you. Very low doses of aspirin can be effective. Your doctor may prescribe a daily
dose anywhere from 81 mg, the amount in a baby aspirin, to 325 mg (regular strength).
You might be surprised to learn that stopping
daily aspirin therapy can have a rebound effect that may increase your risk of heart attack or stroke. If you've
been on daily aspirin therapy and want to stop, it's important to talk to your doctor before making any changes.
Suddenly stopping daily aspirin therapy could have a rebound effect that may trigger a blood clot.
Hermida RC, et al "Ambulatory blood pressure reduction after bedtime
administration in pre-hypertensive patients" ASH Meeting 2008; Abstract