Drug Repurposing in Alzheimer’s Disease: The Need of the Hour

Alzheimer's disease (AD) is a rapidly emerging disease worldwide and the production of new drugs is expensive, time consuming and often unsuccessful. Drug repurposing is an appealing approach used to explore new therapeutic uses of existing drugs with known safety and pharmacokinetic profiles. This paper discusses the current status of drug repurposing for AD, lists some of the most frequently mentioned repurposing candidates and their therapeutic category and discusses methods to validate drug repurposing hypotheses. The current evidence suggests a variety of potential treatments with no clear evidence of candidates to prioritize. There is inconsistent use of validation practices, and limited use of real world evidence. The lack of central nervous system penetration, preclinical limitations of blood–brain barrier models, uncertainty regarding effective dosing and safety, lack of standardized biomarkers, regulatory and commercial restrictions further limit the clinical translation. If this real-world data is integrated with computational screening, better disease models, validated biomarkers and collaborative research, these could help with more reliable candidate selection and could speed up effective AD treatments.