Reacción a "Reactions: use of erectile dysfunction drugs associated with reduced risk of Alzheimer's in men "

This is a large study demonstrating a relationship between prescription of phosphodiesterase type 5 inhibitors and reduced risk of Alzheimer's disease in men. The risk appears to be dose-dependent i.e. higher risk reduction with more prescriptions. It is also more pronounced in people with heart disease risk factors (high blood pressure, diabetes), suggesting that the effect may be due to neuroprotection through vascular mechanisms.  

“The study is limited through the challenge in drawing causal relationships in epidemiological studies. Also, these types of drugs is typically taken as needed, so it is difficult to know how much was actually taken and at what frequency. In addition, the link to Alzheimer's disease in particular is contentious as it is known that a significant proportion of dementia cases diagnosed as Alzheimer's clinically have additional or alternative pathologies.  

“Overall, this is a significant development as repurposing already existing drugs for the prevention of dementia is a promising strategy to stop dementia from developing in the first place using drugs with known safety profile. Clinical trials where these drugs are given against a dummy pill to people at risk are required to decide on their usefulness for dementia prevention. It is worth noting that the blinding of such trials (i.e. ensuring that neither the patients nor researchers know what is given) will be limited given the physiological effects of the drugs.