By Sydney Devine
WebMD Health News
Reviewed by Arefa Cassoobhoy, MD, MPH
"All of these blood pressure medications have been available for decades. They're all FDA-approved. They're cheap. And blood pressure is easily controlled," says researcher Whitney Wharton, PhD, an assistant professor at the Emory University School of Medicine.
Results from the study were presented at the Alzheimer's Association International Conference 2015 in Washington, D.C.
Previous research has shown that having high blood pressure by midlife raises the odds of getting Alzheimer's disease down the road. But treating high BP with any combination of medication or lifestyle changes also appears to lower Alzheimer's risk.
Some medications may be better at cutting the risk than others, though. That's because their size and the way they work allows them to be active in the brain.
Wharton reviewed the medical records of 784 people with high blood pressure who had also been diagnosed with mild cognitive impairment. In other words, they had early changes in thinking and memory that put them at a higher risk for Alzheimer's disease.
All of them were taking medications to lower their blood pressure, and 488 of them were taking ACE inhibitors or ARBs. Both work on the system of hormones that controls blood pressure.
Other types of medications lower BP in different ways. Diuretics are pills that rid the body of water and salt. Calcium channel blockers relax the muscle cells in the heart and blood vessels.
Wharton tracked these people's progress over 3 to 5 years. Those on an ACE inhibitor or an ARB medication were less likely to have their mild cognitive impairment turn into Alzheimer's disease than people taking other kinds of meds.
Among ACE inhibitors and ARBs, only certain drugs are tiny enough to pass through the membranes between the small blood vessels in the head into brain tissue.
When Wharton looked just at people who were taking medications that could cross this so-called blood-brain barrier, she says they had the lowest risk of getting Alzheimer's of all.
"There's something with these types of medications that we think is beneficial for the brain," she says.
A 2009 study also found that people taking ACE inhibitors that were crossing the brain barrier had a 65% lower risk of getting the disease compared to people taking other kinds of BP drugs.
More research is needed to understand the connection. But for people who need blood pressure medication, experts say it's probably not a bad idea to ask your doctor about the kinds of BP drugs that may protect the brain.
"If you have high blood pressure and you are on a blood pressure lowering medication, switching to an ACE inhibitor [or ARB] if you're not on one could be a reasonable request," says Kaycee Sink, MD, an associate professor of gerontology and geriatrics at Wake Forest Baptist Medical Center. She was not involved in the current research.
A 2015 report from the Alzheimer's Association says the number of Americans living with the disease is expected to nearly triple by 2050. Right now there's no way to definitively prevent Alzheimer's, only ways to lower the risk of getting it.
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SOURCES: Whitney Wharton, PhD, Assistant Professor, Emory University School of Medicine, Atlanta. Kaycee Sink, MD, Associate Professor, Wake Forest Baptist Medical Center, Winston-Salem, N.C. Alzheimer's Association International Conference 2015, July 18-23, 2015, Washington, D.C. Alzheimer's Association: "Changing the Trajectory of Alzheimer's disease: How a Treatment by 2025 Saves Lives and Dollars." Sink, K. Archives of Internal Medicine, published online July 13, 2009. Yasar, S. American Academy of Neurology, published online Sept. 3, 2013.
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