By Abigail O’Leary Taking erectile dysfunction drugs such as Viagra could slash the risk of developing Alzheimer’s disease by nearly a fifth, according to a new study. Researchers followed more than 250,000 men diagnosed with erectile dysfunction over a period of five years, and compared those who were prescribed the drugs with those who were not. They found that those who were taking erectile dysfunction drugs were 18% less likely to develop Alzheimer’s. This means drugs such as Viagra – which work by dilating blood vessels to allow more blood to flow through – may also help prevent or delay …