Effects of Doxazosin Gastrointestinal Therapeutic System on Ambulatory Blood Pressure and Cardiovascular Risk Factors in Uncontrolled Hypertensive Patients

This study has been completed.
Information provided by:
ClinicalTrials.gov Identifier:
First received: March 26, 2008
Last updated: August 7, 2008
Last verified: August 2008
The primary objective was to determine the effects of the Gastrointestinal Therapeutic System (GITS) formulation of Doxazosin when used in combination therapy with the 5 major classes of antihypertensive agents as measure by 24-hour diastolic blood pressure.

Condition Intervention Phase
Drug: Doxazosin gastrointestinal therapeutic system (GITS)
Phase 4

Study Type: Interventional
Study Design: Allocation: Non-Randomized
Endpoint Classification: Safety/Efficacy Study
Intervention Model: Single Group Assignment
Masking: Open Label
Primary Purpose: Treatment
Official Title: The Effects of Doxazosin Gastrointestinal Therapeutic System (GITS) on Ambulatory Blood Pressure and Cardiovascular Risk Factors in Uncontrolled Hypertensives on Drug Therapy

Resource links provided by NLM:

Further study details as provided by Pfizer:

Primary Outcome Measures:
  • To determine the effects of Doxazosin Gastrointestinal Therapeutic System (GITS) 4 or 8mg/day on mean 24-hour diastolic ambulatory blood pressure (ABP) when used in combination therapy in subjects with uncontrolled essential hypertension. [ Time Frame: 11 weeks ] [ Designated as safety issue: No ]

Secondary Outcome Measures:
  • Serum lipid levels (total cholesterol [TC], HDL cholesterol, calculated LDL cholesterol, triglycerides, calculated HDL/TC ratio) [ Time Frame: 9 weeks ] [ Designated as safety issue: Yes ]
  • HgbA1C [ Time Frame: 9 weeks ] [ Designated as safety issue: Yes ]
  • 24-hour systolic ABP and 24-hour ambulatory heart rate [ Time Frame: 9 weeks ] [ Designated as safety issue: Yes ]
  • daytime and nighttime (2200 to 0600 hours) ABP and ambulatory heart rate [ Time Frame: 9 weeks ] [ Designated as safety issue: Yes ]
  • Sitting and standing clinic blood pressure (BP) and heart rate [ Time Frame: 9 weeks ] [ Designated as safety issue: Yes ]
  • 24-hour ABP smoothness index [ Time Frame: 9 weeks ] [ Designated as safety issue: Yes ]
  • 24-hour ABP and ambulatory heart rate between 24 hours (Week 9) and 48 hours (Week 9+1 day) after final dose of Doxazosin GITS [ Time Frame: 9 weeks ] [ Designated as safety issue: Yes ]

Enrollment: 89
Study Start Date: February 2003
Study Completion Date: February 2004
Primary Completion Date: February 2004 (Final data collection date for primary outcome measure)
Arms Assigned Interventions
Experimental: A Drug: Doxazosin gastrointestinal therapeutic system (GITS)
4 mg/day, and was titrated, if necessary, to 8 mg/day at Week 3 (Visit 5) or Week 5 (Visit 6).


Ages Eligible for Study:   18 Years and older
Genders Eligible for Study:   Both
Accepts Healthy Volunteers:   No

Inclusion Criteria:

  • Eligible subjects were males or females ≥18 years of age with a diagnosis of primary essential hypertension and currently taking 1 or 2 individual antihypertensive agents
  • Dosing for entry antihypertensive medication was at the accepted efficacious dose or the maximum tolerated dose and had to be stable for at least 4 weeks prior to study entry
  • Subjects were required to have clinic sitting DBP ≥95 and ≤110 mmHg and SBP ≥140 and ≤180 mmHg as an average of 3 readings on their current antihypertensive therapy at visits 1 and 2

Exclusion Criteria:

Exclusion criteria included, but were not limited to:

  • Subjects taking antihypertensive medications for other indications (i.e. arrhythrma, unstable angina, CHF, etc.)
  • Orthostatic hypotension, defined as a decrease of at least 20 mmHg systolic or 1OmmHg diastolic pressure between sitting and standing blood pressures after 2 rmnutes, or known fluid depletion.
  Contacts and Locations
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Please refer to this study by its ClinicalTrials.gov identifier: NCT00646841

Pfizer Investigational Site
Unknown, Nyiregyhaza, Hungary, 4400
Pfizer Investigational Site
Unknown, Co Galway, Ireland
Pfizer Investigational Site
Brescia, Italy, 25123
Pfizer Investigational Site
Monza (Milan), Italy, 20052
Pfizer Investigational Site
Padova, Italy, 35128
Pfizer Investigational Site
Unknown, Jastrzebie Zdroj, Poland, 44-330
Pfizer Investigational Site
Palamos, Gerona, Spain, 17230
Pfizer Investigational Site
Unknown, Oviedo, Spain, 33006
Pfizer Investigational Site
Madrid, Spain, 28041
United Kingdom
Pfizer Investigational Site
London, United Kingdom, EC1M 6BQ
Sponsors and Collaborators
Study Director: Pfizer CT.gov Call Center Pfizer
  More Information

Additional Information:
No publications provided

Responsible Party: Director, Clinical Trial Disclosure Group, Pfizer, Inc.
ClinicalTrials.gov Identifier: NCT00646841     History of Changes
Other Study ID Numbers: A0351051 
Study First Received: March 26, 2008
Last Updated: August 7, 2008
Health Authority: United States: Food and Drug Administration

Keywords provided by Pfizer:
Essential hypertension, doxazosin, ambulatory blood pressure monitoring

Additional relevant MeSH terms:
Adrenergic Agents
Adrenergic Antagonists
Adrenergic alpha-1 Receptor Antagonists
Adrenergic alpha-Antagonists
Antihypertensive Agents
Cardiovascular Agents
Molecular Mechanisms of Pharmacological Action
Neurotransmitter Agents
Pharmacologic Actions
Physiological Effects of Drugs
Therapeutic Uses

ClinicalTrials.gov processed this record on February 10, 2016