Angiotensin II receptor blockers (ARBs) are a class of prescription drugs (e.g., candesartan, telmisartan) that block the action of angiotensin, a hormone that causes blood vessels to constrict. They are primarily used to manage high blood pressure (hypertension), which, especially in mid-life, is a risk factor for Alzheimer's. Some studies suggest that ARBs may be superior to other antihypertensives in reducing the risk of Alzheimer's or preventing cognitive decline. ARBs are generally safe with few side effects.
Observational studies suggest that ARBs may benefit cognition and be superior to other antihypertensives to reduce the risk of Alzheimer's disease, but the evidence is not consistent.
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A meta-analysis and an additional small randomized controlled trial suggested that the use of ARBs may preserve cognition and increase cerebral blood flow more than other antihypertensives in individuals with hypertension . However, two large randomized controlled trials reported that an ARB had no effect on cognition compared to another antihypertensive or a placebo , and one additional trial reported that an ARB only benefitted cognition in individuals with low baseline cognitive function .
A meta-analysis of observational studies suggested that ARBs were associated with a reduced risk of Alzheimer's disease and cognitive impairment due to aging . Another observational study suggested that the use of ARBs was associated with a reduced risk of dementia compared to those using another class of antihypertensives called angiotensin converting enzyme (ACE) inhibitors (e.g., lisinopril, perindopril) . Similar results were reported in other observational studies comparing ARBs to other antihypertensives in patients with hypertension and hypertension with type 2 diabetes . Finally, another observational study suggested that ARB users performed better on memory tasks than those using other antihypertensives and had fewer white matter hyperintensities, a measure of blood vessel damage in the brain .
However, results from the recent SPRINT-MIND trial suggest that intensive blood pressure lowering (<120 vs. <140 systolic blood pressure) may be more important than the choice of blood pressure medication for dementia prevention .
Preclinical studies suggest that ARBs may be beneficial in Alzheimer's disease by reducing amyloid plaques, reducing inflammation, and improving blood flow to the brain [12-18].
Two studies showed there may be elevated levels of angiotensin in patients with Alzheimer's disease . One small clinical trial in Alzheimer's patients reported that individuals taking an ACE inhibitor had worse cognition over six months while those taking an ARB did not . Other observational studies suggested that individuals with Alzheimer's disease who took ARBs may have a reduced mortality risk compared to those taking other antihypertensives . Finally, one study suggested that dementia patients taking ARBs had less biological markers of Alzheimer's after death compared to those taking other antihypertensives .
ARBs are generally safe with side effects similar to a placebo. The most common side effects include headache, respiratory infection, dizziness, and fatigue. Less frequent side effects include hypotension (low blood pressure), kidney failure, and increased potassium levels. They typically have fewer side effects than a similar class of antihypertensives, ACE inhibitors (e.g., lisinopril, perindopril) .
ARBs increase the absorption of lithium by the kidneys, so the use of lithium with ARBs should be avoided. Dual therapy with ARBs and ACE inhibitors may also increase the risk of hypotension, kidney failure, and increased potassium levels . Many drugs interact with ARBs, so concurrent drug use should be discussed with a physician (e.g. telmisartan from Drugs.com).
NOTE: This is not a comprehensive safety evaluation or complete list of potentially harmful drug interactions. It is important to discuss safety issues with your physician before taking any new supplement or medication.
ARBs are available with a prescription and many are available as generic medicines. Starting doses vary depending on the drug (e.g., telmisartan 20-80mg/day, candesartan 8-32mg/day). All ARBs end with the word "sartan." Different classes of antihypertensives are commonly prescribed together and doses are titrated until a target blood pressure is reached.
Results from the SPRINT-MIND trial suggested that intensive blood pressure control (systolic blood pressure <120 vs. <140), regardless of the medication, reduced the risk of mild cognitive impairment (MCI) and the combination of MCI and dementia.
Safety and drug interactions can be found at Drugs.com.
Information on new blood pressure guidelines from the American College of Cardiology and the American Heart Association.
Overview of blood pressure medications from the American Stroke Association.