Target workspace

Phosphodiesterase-5

Enzyme degrading cGMP in smooth muscle.

Pathway & druggability

NO–cGMP signaling

Druggability: High (PDE5 inhibitors approved)

Evidence behind this

Confidence score94%

Signal strength: HighLevel 1 (RCT + regulatory approval)

Evidence grade

Approved

Improved 6-minute walk distance and hemodynamics; FDA approved as Revatio.

Mechanism

PDE5 inhibition elevates pulmonary cGMP, reducing pulmonary vascular resistance.

clinical trialfda labelPhase III

Authoritative sources

PubMed · 12925463
Sildenafil for treatment of lung fibrosis and pulmonary hypertension
Ghofrani HA et al. (2003)
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ClinicalTrials.gov · NCT00033314
Sildenafil in pulmonary arterial hypertension (SUPER-1)
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FDA · 021845
Revatio (sildenafil) FDA approval
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AI-generated summary

Generated March 15, 2026Last verified June 25, 2026

Sildenafil is an established, FDA-approved therapy for PAH with robust Phase III evidence. This is a validated repurposing success from erectile dysfunction research to pulmonary vascular disease.

Source papers

Ghofrani HA et al., 2003

This summary is AI-assisted and human-reviewed. It does not constitute medical advice. Always consult authoritative sources and qualified professionals.