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Diuretics, Hypertension, and Arrhythmias Clinical Trial

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ClinicalTrials.gov Identifier: NCT00000525
Recruitment Status : Completed
First Posted : October 28, 1999
Last Update Posted : September 19, 2013
National Heart, Lung, and Blood Institute (NHLBI)
Information provided by:
University of California, San Francisco

Brief Summary:
To determine whether hypertensive patients with ECG abnormalities and receiving hydrochlorothiazide diuretics were at increased risk of sudden death.

Condition or disease Intervention/treatment Phase
Cardiovascular Diseases Death, Sudden, Cardiac Heart Arrest Heart Diseases Hypertension Drug: hydrochlorothiazide Behavioral: diet, potassium supplementation Behavioral: diet, magnesium supplementation Drug: triamterene Drug: chlorthalidone Phase 3

Detailed Description:


The Multiple Risk Factor Intervention Trial (MRFIT) revealed an unexpected subgroup finding: an association between diuretic therapy (especially with hydrochlorothiazide) and an increased rate of sudden death in hypertensive men with left ventricular hypertrophy and other ECG abnormalities. The Diuretics, Hypertension, and Arrhythmias Clinical Trial sought to determine whether the finding resulted from random variation or represented a serious toxic response to hydrochlorothiazide.


Randomized, double-blind. Following one month of withdrawal from all diuretics and repletion with oral potassium and magnesium, the study participants were randomized to two months of treatment with one of six treatment groups: hydrochlorothiazide; hydrochlorothiazide with oral potassium; hydrochlorothiazide with oral potassium and magnesium; hydrochlorothiazide and triamterene; chlorthalidone; or placebo. The main outcome measures were ventricular arrhythmias on 24-hour Holter monitoring and serum and intracellular potassium and magnesium levels.

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Study Type : Interventional  (Clinical Trial)
Actual Enrollment : 233 participants
Allocation: Randomized
Masking: Double
Study Start Date : July 1986
Actual Primary Completion Date : September 1989

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Ages Eligible for Study:   35 Years to 70 Years   (Adult, Older Adult)
Sexes Eligible for Study:   Male
Accepts Healthy Volunteers:   No

Men, ages 35 to 70, with ECG abnormalities, diastolic blood pressure less than 95 mm Hg at entry.

Subjects had been treated for at least six months by their own physicians with hydrochlorothiazide (HCT), HCT and potassium supplementation, triamteren

Information from the National Library of Medicine

To learn more about this study, you or your doctor may contact the study research staff using the contact information provided by the sponsor.

Please refer to this study by its ClinicalTrials.gov identifier (NCT number): NCT00000525

Sponsors and Collaborators
University of California, San Francisco
National Heart, Lung, and Blood Institute (NHLBI)
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OverallOfficial: Stephen Hulley University of California
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ClinicalTrials.gov Identifier: NCT00000525    
Other Study ID Numbers: 44
R01HL036821 ( U.S. NIH Grant/Contract )
First Posted: October 28, 1999    Key Record Dates
Last Update Posted: September 19, 2013
Last Verified: September 2013
Additional relevant MeSH terms:
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Cardiovascular Diseases
Heart Diseases
Heart Arrest
Death, Sudden, Cardiac
Death, Sudden
Vascular Diseases
Pathologic Processes
Antihypertensive Agents
Natriuretic Agents
Physiological Effects of Drugs
Sodium Chloride Symporter Inhibitors
Membrane Transport Modulators
Molecular Mechanisms of Pharmacological Action
Epithelial Sodium Channel Blockers
Sodium Channel Blockers
Diuretics, Potassium Sparing