Summary: Researchers have identified sildenafil, widely known by the brand name Viagra, as a promising candidate for treating Alzheimer’s disease. Using artificial intelligence to integrate multiple sources of data — including large insurance claims datasets and laboratory observations from patient-derived brain cells — the team found signals that sildenafil may lower the likelihood of an Alzheimer’s diagnosis and reduce levels of neurotoxic proteins linked to the disease.
This body of work supports the idea of repurposing an FDA-approved medicine as a faster, more practical route to new Alzheimer’s therapies. The interdisciplinary study combines computational predictions, real-world patient outcomes and mechanistic laboratory evidence to build a case for clinical trials that will assess sildenafil’s potential benefit in people with or at risk for Alzheimer’s disease.
Key Facts:
- Interdisciplinary approach: The research integrates computational modeling, insurance claims analysis, and experiments on human neurons derived from patient induced pluripotent stem cells (iPSCs), demonstrating a multi-pronged strategy to discover candidate treatments for Alzheimer’s.
- Measured associations: Analysis of two independent de-identified insurance databases showed a 30–54% reduction in Alzheimer’s diagnoses among patients prescribed sildenafil versus comparison groups, after adjusting for demographic and clinical confounders.
- Mechanistic evidence: In neurons derived from Alzheimer’s patients, sildenafil treatment lowered hyperphosphorylated tau species associated with neurotoxicity and changed expression of genes linked to cell growth, reduced inflammation and improved neuronal function.
Source: Cleveland Clinic
Overview of the study
Led by Feixiong Cheng, Ph.D., director of the Cleveland Clinic Genome Center, the study presents converging evidence that supports the candidacy of sildenafil for Alzheimer’s prevention or treatment. Sildenafil is an approved phosphodiesterase-5 inhibitor and is the primary active ingredient in medications marketed for erectile dysfunction (Viagra) and pulmonary arterial hypertension (Revatio).
The research team applied artificial intelligence and computational tools to harmonize and analyze large-scale data from multiple domains. This included millions of de-identified claims records from two independent healthcare databases and laboratory studies that tested sildenafil’s effects on neurons derived from people with familial and sporadic forms of Alzheimer’s disease.
Alzheimer’s disease currently affects more than six million people in the United States, and incidence is projected to rise substantially in coming decades. Given the urgent need for effective treatments, drug repurposing — studying existing, approved medications for new indications — offers a more time- and cost-efficient path compared with developing new compounds from scratch.
Patient data analysis
The investigators examined MarketScan® Medicare Supplemental and the Clinformatics® databases and used propensity score–stratified analyses to account for potential confounding variables such as age, sex, race and comorbid conditions. Across comparisons with several other medications, including spironolactone, bumetanide, furosemide and nifedipine, sildenafil use was associated with a substantially lower incidence or prevalence of Alzheimer’s diagnoses. For example, sildenafil use corresponded to a 54% reduced incidence of Alzheimer’s in the MarketScan cohort (hazard ratio [HR] = 0.46, 95% CI 0.32–0.66) and a 30% reduced prevalence in Clinformatics (HR = 0.70, 95% CI 0.49–1.00) when compared to spironolactone.
Laboratory and mechanistic findings
To explore mechanisms that might explain the epidemiologic associations, the team treated neurons derived from Alzheimer’s patients’ iPSCs with sildenafil. They observed dose-dependent reductions in tau hyperphosphorylation at residues pTau181 and pTau205, molecular changes that are commonly linked to Alzheimer’s pathology. RNA sequencing of treated neurons revealed modulation of gene pathways involved in neuronal growth, synaptic function and inflammation, which are all relevant to neurodegeneration and cognitive resilience.
Taken together, the patient data and cellular-level evidence provide complementary lines of support for the hypothesis that sildenafil could exert protective or disease-modifying effects in Alzheimer’s disease. However, observational findings and mechanistic experiments cannot establish causality on their own.
Next steps and implications
The authors emphasize that randomized controlled trials are necessary to determine whether sildenafil can causally prevent or slow Alzheimer’s disease in humans. The existing safety profile of sildenafil as an FDA-approved drug makes it a strong candidate for repurposing trials, but carefully designed clinical studies are required to assess appropriate dosing, safety in older adults with comorbidities, and meaningful clinical outcomes such as cognitive decline and functional ability.
Dr. Cheng noted that integrating computational predictions with real-world clinical data and mechanistic studies accelerates the discovery pipeline and yields robust, testable hypotheses for clinical research. The multidisciplinary approach used here illustrates how data science, epidemiology and neurobiology can work together to prioritize repurposable drugs for neurodegenerative disease.
Authors and funding
Co-authors include Andrew A. Pieper, M.D., Ph.D., and Jeffrey Cummings, M.D., Sc.D. Co-first authors include Dhruv Gohel, Ph.D., and Amit Gupta, Ph.D. The study received primary support from the National Institute on Aging and the National Institute of Neurological Disorders and Stroke, with multiple NIH award numbers cited in the original report.
About this neuropharmacology and Alzheimer’s disease research news
Author: Alicia Reale
Source: Cleveland Clinic
Contact: Alicia Reale – Cleveland Clinic
Image: The image is credited to Neuroscience News
Original Research: Closed access. The published study is titled “Sildenafil as a Candidate Drug for Alzheimer’s Disease: Real-World Patient Data Observation and Mechanistic Observations from Patient-Induced Pluripotent Stem Cell-Derived Neurons” by Feixiong Cheng et al., in the Journal of Alzheimer’s Disease.
Abstract (condensed)
Background: Alzheimer’s disease is an urgent public health challenge that requires new therapeutic options. Sildenafil, a phosphodiesterase-5 inhibitor already approved for other indications, has been proposed to have potential effects in Alzheimer’s disease.
Objective and methods: The study investigated sildenafil’s potential therapeutic impact by combining large-scale observational analyses from two insurance claims databases with mechanistic experiments using neurons derived from familial and sporadic Alzheimer’s patient iPSCs. Propensity score–stratified analyses adjusted for demographic and clinical confounders.
Results: Observational analyses associated sildenafil use with a 30–54% reduced likelihood of Alzheimer’s diagnosis across several comparator cohorts. In patient-derived neurons, sildenafil reduced tau hyperphosphorylation in a dose-dependent manner and modulated gene pathways related to neuronal health and inflammation.
Conclusions: The combined real-world data and mechanistic observations suggest sildenafil is a plausible repurposable candidate for Alzheimer’s disease. Randomized clinical trials are required to confirm causality and determine whether sildenafil can be an effective therapeutic option for patients with or at risk for Alzheimer’s disease.