Viagra May Be One of Our Best Existing Options For an Alzheimer’s Treatment : ScienceAlert

Repurposing treatments to treat multiple conditions is quicker, safer, and less expensive than developing new ways to manage health.

A recent ranking of existing drugs and vaccines has nominated the erectile dysfunction treatment marketed under the brand name of Viagra as one of our best options to protect individuals against Alzheimer’s disease.

This review comes from a panel of 21 experts who combed through anonymous nominations, clinical evidence, and lay advice, settling on a list of 80 candidates that show potential in treating the neurodegenerative disorder.

Of those candidates, three ultimately stood out: Sildenafil (Viagra), Zostavax (a shingles vaccine), and riluzole (a drug used to treat amyotrophic lateral sclerosis).

These treatments have all been linked to Alzheimer’s prevention by previous studies, but the fact that they’ve been selected by experts as most suitable for future development is a notable endorsement of their potential.

The review used what’s known as a Delphi consensus – a structured process often used in medicine and public health to help groups arrive at decisions that everyone can get behind.

“Each of the priority candidates has evidence supporting relevant underlying mechanisms of action, non-clinical studies, and clinical evidence from epidemiological studies and/or preliminary clinical trials,” write the researchers in their published paper.

“The tolerability of each of these compounds is also suitable for administration to a frailer population of older individuals as part of a well-monitored clinical trial program. We therefore recommend each of these therapeutic approaches as a high priority for clinical trials for the treatment or prevention of Alzheimer’s disease.”

Sildanefil is an inhibitor that relaxes blood vessels, commonly used to promote erections. Past studies have shown how it can also cut Alzheimer’s risk, reducing the toxic accumulation of the tau protein so common in the brains of people with Alzheimer’s.

The Zostavax shingles vaccine is even more promising than Sildanefil, the panel concluded. Though the relationship isn’t fully understood, past studies suggest the vaccine boosts the immune system to protect against Alzheimer’s.

Lastly, there’s riluzole, a drug that prevents neurons from dying by altering biological pathways and reducing levels of brain chemicals previously associated with neurodegenerative diseases like Alzheimer’s.

“Beating dementia will take every avenue of research – from using what we already know, to discovering new drugs to treat and prevent the condition,” says Anne Corbett, a dementia researcher at the University of Exeter in the UK.

“Drug repurposing is a vital part of that mix, helping us turn today’s medicine for one condition, into tomorrow’s treatment for another.”

As promising as these candidates seem, we can’t definitively say these drugs can prevent or reverse Alzheimer’s in human patients yet. The next stage in the process – comprehensive clinical trials – should tell us much more about how helpful these treatments can be.

It’s clear that there are many different potential contributors to Alzheimer’s, and figuring out how they interlink and affect each other is a major challenge for researchers.

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Although much of Alzheimer’s pathology is still something of a mystery, what has been well established is that repurposed drugs can work as treatments for other conditions – and there are reasons to hope that Alzheimer’s disease might be next.

“It’s important to stress that these drugs need further investigation before we will know whether they can be used to treat or prevent Alzheimer’s,” says Corbett.

“We now need to see robust clinical trials to understand their true value and know for certain if they are effective to treat or prevent Alzheimer’s.”

The research has been published in Alzheimer’s Research & Therapy.