Add-on Sildenafil Before Exercise in PAH to See if Max Workload Improves

Is this trial a fit for you?

A plain-English reading of the study's rules. Only the study team can confirm whether you qualify.

What this trial studies

This is a prospective, randomized cross-over trial in adults with PAH that compares additive sildenafil 20 mg taken before exercise to a placebo/dextrose sham. Participants continue their standard PAH therapy, with the intervention timed to assess acute effects on maximum exercise capacity (Wmax). Sildenafil’s rapid onset suggests it could offer immediate improvements in exercise tolerance during CPET. The study aims to determine if a “pill-in-the-pocket” approach can safely enhance functional performance in PAH. Primary outcomes focus on changes in maximum workload during exercise testing.

Why it matters

Who can join: the full rules

Inclusion Criteria:

* Signed Informed consent
* Age 18 - 80 years (both sexes)
* Pulmonary hypertension (PH) class I (PAH) previously diagnosed according to ESC/ERS 2022/2019 guidelines (mPAP ≥ 20 mmHg, PVR ≥ 2 WU, PAWP ≤ 15 mmHg) during diagnostic right-heart catheterization.
* Stable condition, on the same PH-medication for \>4 weeks

Exclusion Criteria:

* Severe resting hypoxia (PaO2 \<7.3 kPa)
* Moderate-to-severe chronic obstructive or restrictive pulmonary disease (FEV1 ≤ 60% predicted, FVC ≤ 60% predicted)
* Women with known pregnancy or breast feeding
* Other clinically significant concomitant disease states (e.g., severe renal or hepatic disease, unstable cardiovascular disease, etc.)
* Concurrent medication with:

  * Nitric oxide donors (molsidomine, nicrorandil, etc.)
  * Soluble guanylate cyclase stimulators (riociguat)
  * Potent CYP3A4 inhibitors (azoles, clarithromycin, protease inhibitors)
* History of anterior ischemic optic neuropathy or hereditary retinal disease
* Participation in another study with investigational drug with potential influence the study data within the 30 days preceding and during the present study.
* Known allergies or hypersensitivity to sildenafil 20mg (Revatio 20mg) or dextrose candy (Dextroenergy) including any of its components

Where it's running

• University Hospital of Zurich, Department of Pulmonology
  Zurich, Canton of Zurich, Switzerland Recruiting

Study contacts

• Principal investigator: Silvia Ulrich, Prof. Dr. med. — University of Zurich
• Study coordinator: Arcangelo F Carta, MD
• Email: arcangelo.carta@usz.ch
• Phone: +41 44 255 22 20

Similar studies

Other studies for the same condition or treatment. Recruiting studies are listed first.

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• Improving adherence to PAH treatment with telemedicine and patient guidance

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How to take part

1. Review the eligibility criteria above with your treating physician.
2. Check the official listing on ClinicalTrials.gov for the latest contact details and recruitment status.
3. Contact the study coordinator or principal investigator to ask for pre-screening. Pre-screening is free and never obligates you to enroll.