Researchers have found that a drug, called nilvadipine that is consumed as a pill to control hypertension, could also help patients combat Alzheimer's disease without affecting other parts of the brain.

Nilvadipine is a calcium channel blocker used to treat high blood pressure (HBP). According to the study published in Hypertension: Journal of the American Heart Association, these findings indicate that the known decrease in cerebral blood flow in patients with Alzheimer's can be reversed in some regions.

"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," said the study lead author Jurgen Claassen, Associate Professor at the Radboud University in the Netherlands.

"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," Claassen said.

For the study, researchers sought to discover whether nilvadipine could help treat Alzheimer's disease by comparing the use of nilvadipine and a placebo among people with mild to moderate Alzheimer's disease. Researchers randomly assigned 44 participants to receive either nilvadipine or a placebo for six months.

They measured blood flow to specific regions of the brain using a unique magnetic resonance imaging (MRI) technique. Results showed that blood flow to the hippocampus, the brain's memory and learning centre, increased by 20 per cent among the nilvadipine group compared to the placebo group.

Blood flow to other regions of the brain was unchanged in both groups. However, the sample sizes were too small and follow-up time too short to reliably study the effects of this cerebral blood flow increase on structural brain measures and cognitive measures, the researchers noted.