Common BP Drugs Tied to Lower Risk of Alzheimer's
Since some classes of meds had the effect but others didn't, more than just blood pressure may be at work
"We did not find any beneficial effect from calcium channel blockers, which was surprising and disappointing," Yasar said. Beta-blockers also were not associated with a reduced risk for Alzheimer's dementia, she said.
Prior studies have suggested that a specific subgroup of calcium channel blockers might still have a protective effect. "It's not a finished story," Yasar said. "There is something to it, but a larger sample size is needed for an analysis of this subgroup."
She also said the study was limited by the fact that the data was collected to assess the effects of ginkgo biloba. As a result, the researchers were not able to determine if the patients took their blood pressure medication as prescribed or if they had used these drugs in the past.
So the question remains: Do certain blood pressure medications reduce the risk for Alzheimer's dementia due to a lowering of blood pressure, or is something else going on?
"The inherent overall health benefit of these medications isn't as clear independent of high blood pressure," McCoyd said. "Do these drugs provide additional benefits in terms of brain health? If that's the case, patients at high risk for brain disease, particularly dementia, may benefit from repurposing these medications."
Blood pressure drugs are already used to treat other conditions independent of blood pressure, such as tremor and headache, McCoyd said. "With so many people affected by [thinking and memory] changes, using these drugs to prevent or delay dementia would probably have the greatest social impact."
McCoyd cautioned, however, that a lot more research is needed before people with normal blood pressure would be automatically prescribed blood pressure drugs to decrease their dementia risk. Although these drugs are widely considered safe, all drugs have side effects, he said. Common side effects of blood pressure medications include dizziness, cough, rash, fatigue, nausea and headache.
More observational studies like this one -- which cannot prove a direct cause-and-effect link -- are not the answer, Yasar said.
"It's time to do clinical trials for these [blood pressure] drugs," she said. "We know these medications lower blood pressure, but could there be something else going on? Our hypothesis is that yes, there is something else."