Taking Viagra regularly could significantly reduce your risk of Alzheimer's, according to Professor Luke O’Neill.

A new study published in the journal Neurology has found that men who were prescribed Viagra and similar medications were 18% less likely to develop Alzheimer’s in later years.

Moreover, the effect appears to increase when you take more of the drug – with researchers finding a 44% fall in risk in men who received between 21 and 50 prescriptions over the course of the study.

“That's a substantial decreased risk and that's what's causing all the excitement,” Prof O’Neill told The Pat Kenny Show today.

“There's what we call a dose dependency in this – the more you take, the lower the risk.”

The Trinity Professor noted that there is the risk of correlation in the study – meaning that the study cannot tell whether Viagra protects against Alzheimer’s or whether men who are already less prone to the disease are more likely to use the tablets.

“Maybe people who take Viagra do something else that helps their brains,” said Professor O’Neill. “And I don't mean sexual activity because that would be tied to this – something else might be in them, we don't know.

“So what they're proposing now is to do a clinical trial in women.

“So if women show protective effects off Viagra, then there's something going on and that might make it more believable.”

Blood flow

Professor O’Neill said there were 260,000 people involved in the current study so the statistics are already “pretty robust”.

He noted that there is also potentially a good reason why Viagra might work.

“What Viagra does is - in case you don't know - it increases blood flow to a certain part of your anatomy and you get ‘lift off’ to put it that way,” he said.

“But it might also increase blood flow to the brain and that might help clear the plaque.

“So there's a rationale you see behind it. That's not unreasonable as a hypothesis.

“What's good is it's already approved as a drug anyway. It's safe, you can get it over the counter now.

“Viagra is extremely safe as a drug and now maybe they'll do a big trial and show it slows down Alzheimer's, which would be a very useful thing for us all.”

Study

The Neurology Journals study analysed medical records for over 260,000 men who were diagnosed with erectile dysfunction but had no evidence of memory or thinking issues.

Just over half were taking PDE5 inhibitor drugs, including Viagra, avanafil, vardenafil and tadalafil.

The men were followed for an average of five years to record any new cases of Alzheimer’s.

You can listen back to Prof O’Neill here: