A cheap pill taken by millions of people to lower blood pressure could also combat Alzheimer’s disease, suggests a new study
The drug, called Nilvadipine, boosts blood flow to the brain’s memory and learning centre by a fifth – without affecting other parts, say scientists.
It belongs to a family of medications called calcium channel blockers. They widen the arteries by stopping the mineral getting in.
Study lead author Professor Jurgen Claassen, of Radboud University Medical Centre in Holland, said: “This high blood pressure treatment holds promise as it doesn’t appear to decrease blood flow to the brain, which could cause more harm than benefit.
“Even though no medical treatment is without risk, getting treatment for high blood pressure could be important to maintain brain health in patients with Alzheimer’s disease.”
Interest is growing in the potential role of blood pressure drugs in the war on dementia. High blood pressure is a known risk factor for the devastating illness.
Prof Claassen’s team recruited 44 patients with mild to moderate Alzheimer’s, half of whom received Nilvadipine for six months and the others a placebo.
Neither the researchers nor the participants knew who were taking the blood pressure pills, which cost a few pence each.
At the outset, both groups underwent a unique MRI (magnetic resonance imaging) scan that measured blood flow to specific areas of grey matter.
When this was repeated at the end, Nilvadipine had increased blood flow to the hippocampus, which controls learning and memory, by 20 percent compared to the dummy drug.
Reduced blood flow to the brain is believed to be a key factor in dementia. The findings published in Hypertension suggest the drug can reverse it.
What’s more, blood flow to other parts of the brain was unaffected in any of the participants.
They were among more than 500 Alzheimer’s patients who had taken part in a study between 2013 and 2015 looking into the potential benefits of Nilvadipine. Their average age was 73, and most were white.
In that larger project, effects on cerebral blood flow were not measured. Overall, no clinical benefit was noted with the use of Nilvadipine.
But a subgroup of patients with only mild symptoms of disease did show benefit, in the sense of a slower decline in memory.
Previous studies have hinted that high blood pressure treatment could reduce the risk of developing dementia.
The researchers believe that beneficial effects on brain blood flow could explain part of this effect.
The study is one of a few to use this MRI technique to probe the effects of treatment on cerebral blood flow, making additional research critical.
An important question is whether this observed increase in cerebral blood flow translates to clinical benefits.
In addition, the small number of participants of similar race and ethnicity mean the results may not apply to other populations.
Prof Claassen added: “In the future, we need to find out whether the improvement in blood flow, especially in the hippocampus, can be used as a supportive treatment to slow down progression of Alzheimer’s disease, especially in earlier stages of disease,”
Alzheimer’s disease is the most common form of dementia. The risk for the disease increases with age and the causes are largely unknown.
Previous research has shown that blood flow to the brain declines in early Alzheimer’s disease.
A British trial is already underway into whether another blood pressure lowering drug called losartan, which first became available in 1995, can slow down the progression of Alzheimer’s.
Experts will use brain imaging to measure whether losartan slashes the rate of brain shrinkage that normally occurs in the disease.
Standard questionnaires on memory performance and quality of life will also indicate whether the drug could be a useful treatment.
Again nobody, including the doctors or nurses involved, will know until the study is analysed who receives which.
There are now 850,000 people living with dementia in the UK – 500,000 of whom have Alzheimer’s, the most common form. The figure is forecast to rise to two million by 2050.