The Influence of Rosiglitazone on the Diuretic Effect of Furosemide and Amiloride

The safety and scientific validity of this study is the responsibility of the study sponsor and investigators. Listing a study does not mean it has been evaluated by the U.S. Federal Government. Read our disclaimer for details. Identifier: NCT00285805
Recruitment Status : Completed
First Posted : February 2, 2006
Last Update Posted : August 24, 2010
Information provided by:
Radboud University

Brief Summary:

Thiazolidinedione derivates (TZD's) are Peroxisome-Proliferator-Activated-Receptor-γ agonists (PPARγ-agonists) and enhance insulin sensitivity. One of the side effects, however, is the fact that subjects treated with these drugs seem to be more prone to fluid retention. The precise mechanism of rosiglitazone-related fluid retention is unknown, but it is clear that either primary or secondary renal sodium retention is part of the mechanism. Furthermore in observational studies, TZD-related oedema seems to be resistant to loop diuretic therapy. The recent finding that rosiglitazone induces upregulation of the epithelial sodium channel (ENaC) in the kidney could be the explanation for TZD-related fluid retention and the observed resistance to loop diuretics. In the present human in-vivo study the following hypothesis will be tested:

Rosiglitazone treatment stimulates the activity of ENaC in the distal nephron, which enhances the natriuretic effect of amiloride and decreases the natriuretic effect of furosemide in parallel.

Condition or disease Intervention/treatment Phase
Insulin Resistance Drug: Rosiglitazone versus placebo Drug: response (sodium excretion) to amiloride infusion Drug: response (sodium excretion) to furosemide infusion Not Applicable

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Detailed Description:

This is a randomized, placebo-controlled, double-blind, single-centre, cross-over study with 4 weeks of wash out comparing placebo with rosiglitazone 4 mg bid for 9 weeks treatment periods. Randomization of the treatment sequence will be computer-generated, with a sequentially driven allocation. Randomization and blinding will be performed at the department of Clinical Pharmacy. After 8 (furosemide) and 9 (amiloride) weeks in each period the end-point experiments will be performed. During all visits (week 0, 4, 8, 9) of each period, adverse events and pill compliance will be recorded. In addition, physical examination, foot volume and bio-impedance measurements will be performed and safety chemical, and hematological profiles will be determined. Only at start and at 8 weeks in each period, glucose, insulin and HbA1c are measured. All visits and interventions will be performed at the Clinical Research Center Nijmegen (CRCN).

Furosemide end-point experiment Each participant will attend the hospital at 8 a.m. after an overnight fast and abstinence of alcohol and caffeine for 20 hours, delivering a 24-hour urine collection and the present morning voiding. The previous three days each participant will adhere to an individualized diet containing 150 mmol of sodium and 80 mmol of potassium prescribed by a dietician. First, blood will be collected to measure fasting glucose and insulin concentrations. Then the subject will be given an individualized breakfast including 1 cup of water. Afterwards a brachial vein will be cannulated and connected to a Braunpump (10 ml/hr NaCl 0.9%), followed by blood drawing for safety and vascular hormone measurements (aldosterone, Atrial Natriuretic Peptide (ANP), Brain Natriuretic Peptide (BNP), Vascular Endothelial Growth Factor (VEGF) and renin).

A bolus of furosemide (40 mg) will be injected through a small cannule in a vein of the contra-lateral arm, just after bladder emptying. Venous blood samples will be drawn at 0, 15, 30, 45, 60, 90,120, 150, 180, 240, 300, 360, 420 and 480 minutes after bolus injection to measure plasma furosemide levels. The participants will be asked to urinate regularly, at least hourly. The exact time of voiding and the urine volume will be recorded. Two urine samples will be taken. In one sample, sodium and creatinine concentrations will be measured while the other sample will be light-protected and immediately frozen for measurement of furosemide levels later on. To prevent dehydration each participant will be asked to drink tap water equal to the volume of diuresis in the previous hour. During the test the participant will be sitting on a bed. At noon the participant will be offered an individualized lunch. After 8 hours each participant will leave the hospital with the instruction to adhere to the diet without fluid restrictions and to collect the urine for up to 24 hours after start of the experiment.

Amiloride end-point experiment Until amiloride infusion the procedures will be similar. At time point 0, venous infusion of a loading dose of amiloride will be started (150 μg/kg in 60 minutes) followed by maintenance infusion (0.20 μg/kg/min) for 4 hours. Amiloride will be obtained as a sterile powder in the form of amiloride HCl/2H2O . Directly before use, the powder will be dissolved in NaCl 0,9% up to a concentration of 1 mg/ml and the solution was filtered through a 0.22 μm Millipore filter. Venous blood for measurement of the amiloride concentration will be sampled at 60, 180, 300 and 420 minutes. All the other procedures will be similar to the furosemide experiment.

Pharmacokinetic considerations on the amiloride-dose The peak plasma levels 3-4 hours after intake of 10 or 20 mg amiloride are 20 μg/L (32) and 38-40 μg/L respectively(33). These concentrations are well below the half maximal inhibitory concentration (IC50) of amiloride for Na+/H+ and Na+/Ca2+-transporters and the α1-receptor, but well above the IC50 for ENaC(34). Using the pharmacokinetic characteristics of amiloride(35) we calculated the required amiloride infusion in order to reach a steady-state concentration between 30-45 μg/L.

Exosome extraction:

Urinary exosomes will be isolated by ultracentrifugation and ENaC abundance will be measured by immunoblotting as previously described (19;36) and normalized to urine creatinine levels. 4 µg of protein lysed in Laemmli buffer will be loaded on 8% SDS-PAGE. PAGE, blotting and blocking of the PVDF membranes will be done as previously described. Membrane will be incubated with 1:4000-diluted affinity-purified rabbit α-ENaC antibody (Rossier BC, Lausanne, Switzerland), followed by 1:5,000-diluted goat anti-rabbit IgG's as secondary antibody coupled to horseradish peroxidase. Blotting signals will be visualized using enhanced chemiluminescence. The samples will be normalized for the expression level of α-ENaC in placebo treatment and indicated as percentage.

Study Type : Interventional  (Clinical Trial)
Actual Enrollment : 13 participants
Allocation: Randomized
Intervention Model: Crossover Assignment
Masking: Triple (Participant, Care Provider, Investigator)
Primary Purpose: Treatment
Official Title: The Influence of Rosiglitazone on the Diuretic Effect of Furosemide and Amiloride. A Double-blind Placebo Controlled Cross Over Study.
Study Start Date : February 2006
Actual Primary Completion Date : October 2006
Actual Study Completion Date : November 2006

Resource links provided by the National Library of Medicine

U.S. FDA Resources

Arm Intervention/treatment
Rosiglitazone-placebo Drug: Rosiglitazone versus placebo Drug: response (sodium excretion) to amiloride infusion Drug: response (sodium excretion) to furosemide infusion
placebo-rosiglitazone Drug: Rosiglitazone versus placebo Drug: response (sodium excretion) to amiloride infusion Drug: response (sodium excretion) to furosemide infusion

Primary Outcome Measures :
  1. Difference in cumulative sodium excretion over an 8-hour period following amiloride infusion after 9 weeks of treatment with either rosiglitazone or placebo. [ Time Frame: week: 9, 22 ]

Secondary Outcome Measures :
  1. The difference in ER50 (urine excretion rate of furosemide with the half maximal effect) after 8 weeks of treatment with either rosiglitazone or placebo. [ Time Frame: week: 8, 21 ]
  2. The difference in the ENac abundance in exosomes in the urine measured after 8 weeks of treatment with either rosiglitazone or placebo [ Time Frame: week: 8, 21 ]

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Ages Eligible for Study:   30 Years to 70 Years   (Adult, Senior)
Sexes Eligible for Study:   All
Accepts Healthy Volunteers:   Yes

Inclusion Criteria:

  • Healthy but with 2 features of the metabolic syndrome (AHA/NHLBI) (16)
  • Willing and able to provide a signed and dated written informed consent.
  • Male or female subject aged between 30 and 70 years

Exclusion Criteria:

  • Fasting glucose > 7,0 mmol/L or the use of hypoglycaemic agents. If fasting plasma glucose is between 6.1 and 7,0 mmol/L,an oral 75 g glucose test will be performed to exclude diabetes mellitus.
  • Exposure to a PPAR-g agonist during the last 4 months or a documented significant hypersensitivity to a PPAR-g agonist.
  • Participant in another study.
  • Angina or heart failure (NYHA I-IV).
  • Clinically significant liver disease (3 times the upper normal limit of ALAT, ASAT, AF, γGT or LDH)
  • Clinically significant anaemia (male Hb < 6,9 mmol/L, female < 6,25 mmol/L)
  • Creatinin clearance < 40 mL/min
  • Pregnancy, lactation
  • Alcohol or drug abuse. Liquorice

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 identifier (NCT number): NCT00285805

Radboud University Nijmegen medical centre
Nijmegen, Netherlands, 6500 HB
Sponsors and Collaborators
Radboud University
Principal Investigator: Paul Smits, MD, PhD Radboud University Nijmegen Medical Centre, head of department Pharmacology and Toxicology.
Principal Investigator: Cees JJ Tack, MD, PhD Radboud University Nijmegen Medical Centre, chairman of the departement of diabetology


Responsible Party: Paul Smits, Radboud University Nijmegen Medical Center Identifier: NCT00285805     History of Changes
Other Study ID Numbers: AR-49653-3
First Posted: February 2, 2006    Key Record Dates
Last Update Posted: August 24, 2010
Last Verified: October 2008

Keywords provided by Radboud University:
Epithelial sodium channel
Sodium excretion

Additional relevant MeSH terms:
Insulin Resistance
Glucose Metabolism Disorders
Metabolic Diseases
Natriuretic Agents
Physiological Effects of Drugs
Sodium Potassium Chloride Symporter Inhibitors
Membrane Transport Modulators
Molecular Mechanisms of Pharmacological Action
Hypoglycemic Agents
Acid Sensing Ion Channel Blockers
Sodium Channel Blockers
Epithelial Sodium Channel Blockers
Diuretics, Potassium Sparing