Viagra-type drugs could have potential for treating some patients with vascular dementia, a UK/US study has found.
A phase II trial, led by researchers at St George’s, University of London and St George’s Hospital was undertaken to test if tadalafil increases brain blood flow in older men and women with narrowing of the brain arteries, which can cause strokes and vascular dementia.
Although the trial found no significant increase in blood flow, the team, writing in *Alzheimer’s & Dementia*, said some of the results merited further investigation.
A recent computational analysis identified sildenafil and vardenafil, drugs commonly used to increase blood flow in erectile dysfunction and in pulmonary hypertension as possible candidates for preventing or delaying dementia.
The research team said because tadalafil belongs to the same group of drugs, they wanted to test if the mechanisms that increase blood flow in other parts of the body could also apply in the brain.
The trial compared a single dose of tadalafil with placebo and researchers recorded the brain blood flow using arterial spin labelling, an MRI-based method.
While the team did not detect a significant difference in blood flow between those given tadalafil and those given a placebo, there was a trend identified for increased blood flow in participants over the age of 70 in the white matter of the brain, which is the area most important for vascular dementia.
They say there should be further investigation into whether or not tadalafil could be effective in older age groups over a longer time period.
Principal clinical investigator Dr Jeremy Isaacs, consultant neurologist at St George’s Hospital, said: “Narrowing of the brain arteries is a common contributor to cognitive decline in older people and currently has no treatment.
“This was a landmark study in which we attempted to reverse the reduction in brain blood flow characteristic of this condition. Although we did not find a significant effect following a single dose of tadalafil, we can’t rule out the possibility of benefits from longer term use, for which further research is needed.”
Katherine Gray, research communications manager at Alzheimer’s Society, added: “Although it’s disappointing that tadalafil did not have a significant effect overall, it’s promising that people over the age of 70 did have an increase in blood flow to certain areas of the brain, and we now hope to now see further tests for different doses over a longer period of time.”
Pauls MMH, Binnie LR, Benjamin P, et al. The PASTIS trial: Testing tadalafil for possible use in vascular cognitive impairment. *Alzheimer’s Dement.* 8 February 2022;1-10
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