Patients often begin dialysis taking diuretics (stimulate the kidney to excrete salt and water). Once on dialysis, these drugs are often continued. Whether these drugs are still needed, or even effective is often unclear.This study,by evaluating the composition of the patients' urine when off the drug, will predict which patients should benefit from the drug. By comparing their 24 hour volume both off and on the drug, the impact of the drug will be established. The results will allow the prediction of which patients, in the future, should take the drug. The hypothesis is: Among dialysis recipients, evaluation of the random urine sodium concentration will help predict the likelihood of a positive response to Furosemide, as manifested by an increased urine volume and sodium excretion.

Brief Title

The Use of Furosemide in Patients on Dialysis

Official Title

The Determinants of the Effectiveness of the Use of Furosemide in Patients on Dialysis

Brief Summary

Patients often begin dialysis taking diuretics (stimulate the kidney to excrete salt and<br /> water). Once on dialysis, these drugs are often continued. Whether these drugs are still<br /> needed, or even effective is often unclear.This study,by evaluating the composition of the<br /> patients' urine when off the drug, will predict which patients should benefit from the drug.<br /> By comparing their 24 hour volume both off and on the drug, the impact of the drug will be<br /> established. The results will allow the prediction of which patients, in the future, should<br /> take the drug. The hypothesis is: Among dialysis recipients, evaluation of the random urine<br /> sodium concentration will help predict the likelihood of a positive response to Furosemide,<br /> as manifested by an increased urine volume and sodium excretion.

Detailed Description

Patients often begin dialysis on a significant dose of diuretic due to the retention of
sodium and water in the predialysis phase of their chronic kidney disease (CKD). The quandary
often faced by the care team is whether or not the diuretic should be continued on dialysis,
particularly after they have been on dialysis for a period of time. For the appropriate
dialysis patient, a daily dose of furosemide,, minimizes the interdialytic weight gain, may
result in better blood pressure (BP) control and may lower the risk of heart failure.
Furthermore, there may be a favourable impact on cardiac remodeling and cardiac morbidity and
mortality. The diuretic may also increase the excretion of potassium, thereby reducing the
likelihood of hyperkalemia.

Patients with significant renal sodium reabsorption would be the ones who would be expected
to respond to furosemide. Thus patients whose urine [Na] is less than 80 mM are reabsorbing
significant amounts of filtered Na (glomerular filtrate [Na] would be between 130 and 140mM)
and thus might be expected to respond to furosemide. (This is premised on the assumption that
the urine [Na] does not vary much during the day in chronic dialysis recipients, but this
will be established during the course of the study.)

The patients Dry Weight will be optimized prior to entry into study according to usual care:
this involves integrating BP data, the central venous pressure as assessed by the internal
jugular vein, and patient symptoms (eg,dyspnea during the interdialytic interval,prolonged
lightheadedness/presyncope/fatigue after dialysis)..

Patients on dialysis who are taking furosemide will be asked to stop their furosemide for 2
weeks, and their dry weight maintained with ultrafiltration on dialysis alone.

After 2 weeks, to establish whether there is any diurnal variation in the urine [Na] they
will collect their urine in separate containers, appropriately labeled with the date and
time, during the 24 hr period ending pre dialysis after the long interdialytic interval.
These collections will also determine whether there is any diurnal variation in [Na], the
individual urine [Na], as well as indicate the 24 hour urine volume and Na excretion off the
furosemide.

All urine samples will be assayed for the concentration of Na, K, and creatinine, as well as
their volume.

Thereafter, each patient will be given furosemide 120 mgm every morning for 2 weeks and they
will collect the urine voided with each voiding (labeling with the time voided) in separate
containers during the 24 hr period ending pre dialysis after the long interdialytic interval
after 2 weeks . These collections will answer whether there is any diurnal variation in [Na]
while on furosemide, as well as determine the 24 hour urine volume and Na excretion on the
furosemide.

The results will determine whether those patients taking furosemide are indeed benefitting
from it (Na, K and H2O excretion) and will help one to predict whether patients not taking
furosemide, might indeed benefit from taking it.

At the conclusion of the 2-week period of furosemide therapy, the patient's primary
nephrologist will determine the need for continuing this agent and if a decision is made to
continue furosemide, the dose would be at the discretion of the nephrologist.

The primary outcome is the increase in urine volume and 24 hour sodium excretion in response
to the furosemide therapy

Outcome Measures

Outcome measures are the tests that investigators perform to prove whether or not a treatment being tested in a clinical trial is having any effect.