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Completed Phase 3 Interventional

A Study to Assess the Efficacy and Safety of 20, 40, and 80mg of Sildenafil Three Times a Day in the Treatment of Pulmonary Arterial Hypertension

ClinicalTrials.gov ID: NCT00644605

Public ClinicalTrials.gov record NCT00644605. Field values are reproduced from the official study page; the official ClinicalTrials.gov record remains the source of truth for eligibility, enrollment, and contact information.

ClinicalTrials.gov public records Last synced Sep 23, 2026, 8:21 PM EDT

Data is sourced from official ClinicalTrials.gov public API records. Always review the official ClinicalTrials.gov record for the latest information.

Official title

A Multinational, Multi-centre, Randomised, Double-blind, Double-dummy, Placebo-controlled Study to Assess the Efficacy and Safety of 20, 40, and 80mg TID Sildenafil in the Treatment of Pulmonary Arterial Hypertension in Subjects Aged 18 Years and Over

Brief summary

Reproduced verbatim from the official ClinicalTrials.gov record. Not medical advice.

To evaluate the effect of three doses of oral sildenafil (20, 40 and 80 mg three times a day \[TID\]) on exercise capacity, as measured by the 6-Minute Walk test, as well as the safety and tolerability, after 12 weeks of treatment in subjects with pulmonary arterial hypertension who are aged 18 years and over. To investigate the plasma concentration-effect relationship and to determine the population pharmacokinetic (PK) parameters.

Study identification

NCT ID
NCT00644605
Recruitment status
Completed
Study type
Interventional
Phase
Phase 3
Enrollment
275 participants

Conditions and interventions

Interventions

Drug

Eligibility (public fields only)

Age range
18 Years and older
Sex
All
Healthy volunteers
Healthy volunteers not accepted

This page does not interpret eligibility. Detailed inclusion and exclusion criteria are on the official ClinicalTrials.gov record.

Study timeline

Start date
Sep 30, 2002
Primary completion
Not listed
Completion
Oct 31, 2003
Last update posted
Jan 31, 2021

2002 – 2003

United States locations

U.S. sites
24
U.S. states
14
U.S. cities
18
Facility City State ZIP Site status
Pfizer Investigational Site Birmingham Alabama 35233
Pfizer Investigational Site Birmingham Alabama 35294-0006
Pfizer Investigational Site Birmingham Alabama 35294
Pfizer Investigational Site La Jolla California 92037
Pfizer Investigational Site La Jolla California 92093
Pfizer Investigational Site Los Angeles California 90024
Pfizer Investigational Site Los Angeles California 90033
Pfizer Investigational Site Los Angeles California 90095
Pfizer Investigational Site San Diego California 92037
Pfizer Investigational Site Torrance California 90502
Pfizer Investigational Site Torrance California 90509
Pfizer Investigational Site Aurora Colorado 80010
Pfizer Investigational Site Denver Colorado 80262
Pfizer Investigational Site Chicago Illinois 60612
Pfizer Investigational Site Shreveport Louisiana 71103
Pfizer Investigational Site Baltimore Maryland 21205
Pfizer Investigational Site Boston Massachusetts 02111
Pfizer Investigational Site Ann Arbor Michigan 48109
Pfizer Investigational Site Rochester Minnesota 55905
Pfizer Investigational Site New York New York 10032
Pfizer Investigational Site Durham North Carolina 27710
Pfizer Investigational Site Nashville Tennessee 37232
Pfizer Investigational Site Houston Texas 77030
Pfizer Investigational Site Milwaukee Wisconsin 53215

Site contact phone numbers, emails, and investigator names are intentionally not displayed here. Open the official ClinicalTrials.gov record for site contact information.

Non-U.S. locations

This page focuses on the U.S. directory. The official record also lists 44 non-U.S. sites.

About this trial record page

What this page shows
Public field values for ClinicalTrials.gov record NCT00644605, including study identification, conditions, interventions, eligibility (age, sex, healthy volunteer), timeline, and U.S. site list.
What this page does not do
No medical advice, eligibility judgments, treatment recommendations, study quality scoring, or AI-generated medical summaries. No site contact phone numbers, emails, or investigator names.
Where the data comes from
Sourced from the official ClinicalTrials.gov public API. The official record is the source of truth.
Last refresh
Last update posted Jan 31, 2021 · Synced Sep 23, 2026

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Open the official record

The complete protocol, eligibility criteria, and contact information for NCT00644605 live on ClinicalTrials.gov.

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