A systematic review analyzed data from over 130 million patients and identified key medications linked to both increased and decreased dementia risk. Results indicated that antimicrobials, anti-inflammatories, and vaccines were associated with reduced dementia risk, while antipsychotics, antidepressants, and diabetes medications were frequently associated with increased dementia risk. Reverse causation is a concern, as medications may be prescribed for early dementia symptoms. Further investigation is warranted to refine causal inference and assess the potential for drug repurposing strategies.