The Effect of Additive On-Demand Sildenafil vs. Dextrose Candy on Maximum Exercise Capacity in Pulmonary Arterial Hypertension

NCT07824674 | Recruiting Phase 2

• 1 other identifier: KEK-ZH-Nr. 2025-02557
• Study Type: interventional
• Target: 20
• Locations: 1 country
• Sites: 1

Brief Summary

The goal of this clinical study is to investigate whether the additional intake of sildenafil 20mg on top of standard medical treatment results in a benefit on maximum exercise workload (Wmax) in patients with pulmonary arterial hypertension (PAH).

Conditions

Pulmonary Arterial Hypertension (PAH) (WHO Group 1 PH)

Keywords

Sildenafil; Pulmonary Arterial Hypertension; Cardiopulmonary Testing; RCT; CPET; CWRET; Pill-In-The-Pocket

Outcome Measures

Primary Outcomes (1)

• Maximum workload (Wmax)

  The difference in maximum workload (Wmax) attained during maximum spiroergometry 45 minutes after treatment with Sildenafil 20mg (Revatio 20mg) versus dextrose candy (Dextro Energy).

  Within 1 - 90 days

Secondary Outcomes (31)

• Time to Exhaustion (Tmax)

  Within 1 - 90 days

• Cardiometabolic parameters (CPET, CWRET): Oxygen Saturation (SpO2)

  Within 1 - 90 days

• Focused Stress-Echocardiography (Right Heart): Stroke Volume (SV)

  Within 1 - 90 days

• Arterial blood gases: Arterial Partial Pressure of Oxygen (PaO2)

  Within 1 - 90 days

• Borg CR10 (Borg Category-Ratio 10 Scale)

  Within 1 - 90 days

Other Outcomes (1)

• Safety Profile / (S)AEs

  (S)AEs will be assessed immediately after each intervention (A or B) during the corresponding study visits (1 and 2).

Study Arms (2)

Intervention Order A

OTHER

Group A will receive the active comparator first (Sildenafil 20mg) in accordance with the Cross-Over trial design.

Drug: Dextrose; Drug: Sildenafil 20mg

Intervention Order B

OTHER

Group B will receive the placebo comparator first (Dextrose Candy) in accordance with the Cross-Over trial design.

Drug: Dextrose; Drug: Sildenafil 20mg

Interventions

Dextrose DRUG

Administration of Dextrose Candy by mouth as a tablet.

Also known as: Dextro Energy, Dextrose Candy

Intervention Order A; Intervention Order B

Sildenafil 20mg DRUG

Administration of Sildenafil 20mg by mouth as a tablet.

Also known as: Revatio 20mg

Intervention Order A; Intervention Order B

Eligibility Criteria

• Age: 18 Years - 80 Years
• Sex: all
• Healthy Volunteers: No
• Age Groups: Adult (18-64), Older Adult (65+)

You may qualify if:

• 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

You may not qualify if:

• 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

Sponsors & Collaborators

• Silvia Ulrich: lead

Study Sites (1)

University Hospital of Zurich, Department of Pulmonology

Zurich, Canton of Zurich, 8091, Switzerland

RECRUITING

MeSH Terms

Conditions

Pulmonary Arterial Hypertension

Interventions

Glucose; Sildenafil Citrate

Condition Hierarchy (Ancestors)

Hypertension, Pulmonary; Lung Diseases; Respiratory Tract Diseases

Intervention Hierarchy (Ancestors)

Hexoses; Monosaccharides; Sugars; Carbohydrates; Sulfonamides; Amides; Organic Chemicals; Sulfones; Sulfur Compounds; Piperazines; Heterocyclic Compounds, 1-Ring; Heterocyclic Compounds; Purines; Heterocyclic Compounds, 2-Ring; Heterocyclic Compounds, Fused-Ring

Study Officials

• Silvia Ulrich, Prof. Dr. med.

  University of Zurich

  PRINCIPAL INVESTIGATOR

• Arcangelo F Carta, Dr. med.

  University of Zurich

  PRINCIPAL INVESTIGATOR

Central Study Contacts

Arcangelo F Carta, MD

CONTACT

+41 44 255 22 20; arcangelo.carta@usz.ch

Silvia Ulrich, Prof. MD

CONTACT

+41 44 255 22 21; silvia.ulrich@usz.ch

Study Design

• Study Type: interventional
• Phase: phase 2
• Allocation: RANDOMIZED
• Masking: SINGLE
• Who Masked: OUTCOMES ASSESSOR
• Purpose: TREATMENT
• Intervention Model: CROSSOVER
• Sponsor Type: OTHER
• Responsible Party: SPONSOR INVESTIGATOR
• PI Title: Prof. Dr. med.

Model Details: Randomized, Cross-Over Trial

Study Record Dates

• First Submitted: August 17, 2026
• First Posted: September 17, 2026
• Study Start: September 1, 2026
• Primary Completion (Estimated): April 1, 2028
• Study Completion (Estimated): December 1, 2028
• Last Updated: September 17, 2026

Record last verified: 2026-09

Data Sharing

• IPD Sharing: Will not share

Locations

CH (1)