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Sil3.8

Sildenafil (Viagra) Research

Mostly mechanism / observationalModerate safety

6 peer-reviewed studies

What the evidence says

Mostly mechanism / observational

Most Sildenafil (Viagra) studies are mechanism or observational rather than RCTs that measure a clinical effect — keep findings provisional.

Most evidence is from mixed-quality meta-analyses and randomised trials published 1998–2023.

Based on 6 studies · 1 meta-analysis · 2 RCTs

Confidence

Moderate

By outcome

Erectile function
Mostly mechanism / observational4 studies
Cardiovascular & vascular
Mostly mechanism / observational3 studies
Dementia risk (associational)
Too few graded studies2 studies
Mortality (associational)
Too few graded studies1 study
Safety profile
Too few graded studies1 study

Active research area

3 studies in the last 5 years · Latest meta-analysis: 2006

199820102023

1RCT1998

Oral sildenafil is an effective, well-tolerated treatment for men with erectile dysfunction.

Goldstein, Lue, Padma-Nathan, Rosen, Steers, Wicker · The New England Journal of Medicine (1998)

Two sequential double-blind randomized trials of on-demand oral sildenafil in men with erectile dysfunction
Dose-dependent improvement in erections and successful intercourse versus placebo
Common adverse effects were headache, flushing, dyspepsia, and transient visual disturbance

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2RCT2005

Sildenafil improved exercise capacity, hemodynamics, and WHO functional class in pulmonary arterial hypertension.

Galiè, Ghofrani, Torbicki, Barst, Rubin, Badesch · The New England Journal of Medicine (2005)

SUPER-1: randomized, double-blind, placebo-controlled trial in 278 patients with PAH
Sildenafil improved 6-minute walk distance, hemodynamics, and functional class across doses
Basis for FDA approval of sildenafil (Revatio) for pulmonary arterial hypertension

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3Meta-Analysis2006

All PDE5 inhibitors meaningfully improved erectile function on the IIEF versus placebo, with sildenafil among the most effective.

Berner, Kriston, Harms · International Journal of Impotence Research (2006)

Comparative meta-analysis pooling fixed-dose RCTs of sildenafil, tadalafil, and vardenafil
All agents produced clinically meaningful IIEF improvement versus placebo
Sildenafil at maximum dose was among the most effective for erectile function

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4Cohort2021

Among men with prior MI or revascularization, PDE5-inhibitor use was associated with lower long-term mortality than alprostadil.

Andersson, Landucci, Lagerros, Grotta, Bonamy, Krane · Journal of the American College of Cardiology (2021)

Swedish nationwide cohort of men with stable coronary artery disease treated for erectile dysfunction
PDE5-inhibitor use associated with lower all-cause and cardiovascular mortality versus alprostadil
Association was dose-dependent and stronger in younger men

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5Observational2021

Sildenafil use was associated with a significantly reduced incidence of Alzheimer's disease in insurance-claims analyses.

Fang, Zhang, Zhou, Chiang, Tan, Hou, Cheng · Nature Aging (2021)

Network-medicine prioritization combined with insurance-claims pharmacoepidemiology (~7.2 million people)
Sildenafil use associated with markedly lower Alzheimer's incidence versus comparators
Mechanistic plus epidemiological strand of the dementia hypothesis

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6Observational2023

A big-data analysis associated sildenafil use with a reduced risk of Alzheimer's disease.

Huo, Finkelstein · Studies in Health Technology and Informatics (2023)

Large real-world database study linking sildenafil use to lower Alzheimer's incidence
Supports a vascular/neuroprotective hypothesis for the class
Adds independent real-world replication to the Alzheimer's association

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View in Research Library

Sildenafil (Viagra) Research

Mostly mechanism / observational

Oral sildenafil in the treatment of erectile dysfunction.

Sildenafil citrate therapy for pulmonary arterial hypertension.

Efficacy of PDE-5-inhibitors for erectile dysfunction. A comparative meta-analysis of fixed-dose regimen randomized controlled trials administering the International Index of Erectile Function in broad-spectrum populations.

Association of Phosphodiesterase-5 Inhibitors Versus Alprostadil With Survival in Men With Coronary Artery Disease.

Endophenotype-based in silico network medicine discovery combined with insurance record data mining identifies sildenafil as a candidate drug for Alzheimer's disease.

Using Big Data to Uncover Association Between Sildenafil Use and Reduced Risk of Alzheimer's Disease.