Acute Hemodynamic Effect of Acetazolamide in Pulmonary Hypertension

Study Purpose

To study the acute effect of acetazolamide (AZA) on pulmonary hemodynamics in patients with pulmonary hypertension (PH) undergoing clinically indicated right heart catheterisation (RHC).

Recruitment Criteria

Accepts Healthy Volunteers

Healthy volunteers are participants who do not have a disease or condition, or related conditions or symptoms

Study Type

An interventional clinical study is where participants are assigned to receive one or more interventions (or no intervention) so that researchers can evaluate the effects of the interventions on biomedical or health-related outcomes.

An observational clinical study is where participants identified as belonging to study groups are assessed for biomedical or health outcomes.

Searching Both is inclusive of interventional and observational studies.

Eligible Ages 20 Years - 80 Years
Gender All
More Inclusion & Exclusion Criteria

Inclusion Criteria:

  • - All patients undergoing RHC for a clinical indication and who are diagnosed with precapillary PH (mPAP ≥25 mmHg, pulmonary wedge pressure (PAWP) ≤15mmHg)

    Exclusion Criteria:

    - Patients in whom a RHC is clinically not indicated - pregnant women - PH in left heart disease or with more than mild chronic obstructive pulmonary disease or restrictive lung disease.

Trial Details

Trial ID:

This trial id was obtained from, a service of the U.S. National Institutes of Health, providing information on publicly and privately supported clinical studies of human participants with locations in all 50 States and in 196 countries.


Phase 1: Studies that emphasize safety and how the drug is metabolized and excreted in humans.

Phase 2: Studies that gather preliminary data on effectiveness (whether the drug works in people who have a certain disease or condition) and additional safety data.

Phase 3: Studies that gather more information about safety and effectiveness by studying different populations and different dosages and by using the drug in combination with other drugs.

Phase 4: Studies occurring after FDA has approved a drug for marketing, efficacy, or optimal use.

Phase 2/Phase 3
Lead Sponsor

The sponsor is the organization or person who oversees the clinical study and is responsible for analyzing the study data.

University of Zurich
Principal Investigator

The person who is responsible for the scientific and technical direction of the entire clinical study.

Silvia Ulrich, MD
Principal Investigator Affiliation UniversityHospital Zurich
Agency Class

Category of organization(s) involved as sponsor (and collaborator) supporting the trial.

Overall Status Recruiting
Countries Switzerland

The disease, disorder, syndrome, illness, or injury that is being studied.

Hypertension, Pulmonary
Additional Details

Pulmonary hypertension (PH) of various etiologies causes dyspnea, impairs exercise performance and is associated with reduced quality of life (QoL) and survival. Treatment options include therapy for any underlying causes, pulmonary vasodilator drugs, oxygen and, in selected cases, pulmonary endarterectomy or lung transplantation. Unfortunately, PH specific drugs are expensive, associated with side effects and even combined pharmacological treatment is often not sufficient to achieve clinical benefits. Therefore, novel therapeutic drugs are needed. The investigators have recently demonstrated that sleep related breathing disorders, which are common in PH patients, can be improved by both nocturnal oxygen therapy and acetazolamide (AZA). AZA is a carbonic anhydrase (CA) inhibitor that acts as a respiratory stimulant thereby improving oxygenation and possibly PH. There are even data suggesting that CA-inhibitors have a direct pulmonary vasodilator effect. However, the potential role of AZA in the treatment of PH has not been conclusively studied. Therefore, the purpose of the current project is to investigate, the acute hemodynamic clinical effects of AZA in PH patients.

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International Sites

University Hospital Zurich, Zurich, Switzerland




University Hospital Zurich

Zurich, , 8091

Site Contact

Silvia Ulrich, Prof


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