Extracellular Fluid in Resistant Hypertension

The optimal treatment of drug resistant (defined as BP> 140/85 despite three anti-hypertensive drugs including a diuretic) is not well defined. This study aims to test the hypothesis that resistant hypertension is caused by excessive expansion of extracellular fluid volume. A secondary objective is to study which of three different antihypertensive drugs would be most useful in drug resistant...

Date First Received: August 31, 2005

Last Updated: May 10, 2007

Verified by: St George's, University of London, May 2007

Clinical Trial Phase: N/A | Start Date: July 2003

Overall Status: Recruiting

Estimated Enrollment: 32

Brief Summary

Official Title: “A Study to Investigate the Contribution of Extracellular Fluid Volume Expansion to Drug Resistant Hypertension”

Condition Keyword(s):

The optimal treatment of drug resistant (defined as BP> 140/85 despite three anti-hypertensive drugs including a diuretic) is not well defined. This study aims to test the hypothesis that resistant hypertension is caused by excessive expansion of extracellular fluid volume. A secondary objective is to study which of three different antihypertensive drugs would be most useful in drug resistant hypertension.

Study Type: Interventional

Study Design: Treatment, Randomized, Open Label, Placebo Control, Crossover Assignment, Safety/Efficacy Study

Detailed Clinical Trial Description

Following recruitment subjects will have ECV measured by 51Cr-EDTA determination of GFR, with Brochner-Mortensen correction applied. Subjects then receive the following drugs, in a randomised fashion, for a period of four weeks each, with BP & ECV measurement at end of each period: doxazosin GITS (Cardura XL) 4 mg b.d.; frusemide 40 mg b.d.; amiloride 5 mg b.d.; placebo.

Intervention(s) in this Clinical Trial

  • Drug: Cardura XL 4 mg bd
  • Drug: Amiloride 5 mg bd
  • Drug: Furosemide 40 mg bd

Outcome Measures for this Clinical Trial

Primary Measures

  • Change in ECV; change in BP

Criteria for Participation in this Clinical Trial

Inclusion Criteria:

  • BP >140/85
  • 3 antihypertensive drugs (ACE/ARB + calcium channel blocker + thiazide diuretic)

Exclusion Criteria:

  • Pregnancy
  • Breast Feeding
  • Unstable heart failure
  • Chronic Liver Disease
  • Creatinine >120 mcmol/L
  • Contraindication to (or intolerance of) drug used in study
  • BP > 180/110

Gender Eligibility for this Clinical Trial: Both

Minimum Age for this Clinical Trial: 18 Years

Maximum Age for this Clinical Trial: 80 Years

Are Healthy Volunteers Accepted for this Clinical Trial?: No

Clinical Trial Sponsor Information

Lead Sponsor: St George's, University of London

Overall Clinical Trial Officials and Contacts

Timothy WR Doulton, BSc MRCP Principal Investigator SGUL  

Overall Contact: Timothy WR Doulton, BSc MRCP +44 208 725 3176 tdoulton@sgul.ac.uk

Additional Information

Information obtained from ClinicalTrials.gov on July 02, 2009

Link to the current ClinicalTrials.gov record. http://clinicaltrials.gov/show/NCT00141596

Study ID Number: LREC 03.0001

ClinicalTrials.gov Identifier: NCT00141596

Health Authority: United Kingdom: Research Ethics Committee

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