worsening HF more effectively than furosemide23, but this finding, which was published as an abstract and never translated into a full-length paper, remains controversial.
In outpatients with HF, therapy is commonly initiated with low doses of a diuretic, and the dose is increased until urine output increases and weight decreases, generally by 0.5 to 1.0 kg daily. The ultimate goal of treatment is to eliminate physical signs of fluid retention, either by restoring jugular venous pressures toward normal or by eliminating the presence of edema, or both. When the ideal weight has been achieved, daily weighing should be suggested to the patient in order to prevent relapsing fluid retention. If a gain of weight is seen, despite the moderate dietary sodium restriction (less than 3 g daily) and a consistent alimentary intake, further increases in the dose or frequency of diuretic administration may be required to maintain an active diuresis and sustain the loss of weight.
If electrolyte imbalances are seen, these should be treated aggressively, but the diuretic should not be discontinued.
If hypotension or increased azotemia is observed before the goals of treatment are achieved, the physician may elect to slow the rapidity of diuresis, but diuresis should nevertheless be maintained until fluid retention is eliminated, even if this strategy results in mild or moderate decreases in blood pressure or renal function, as long as the patient remains asymptomatic.
Excessive concern about hypotension and azotemia can lead to the underutilization of diuretics and a state of refractory edema. Persistent volume overload not only contributes to the persistence of symptoms but may also limit the efficacy and compromise the safety of other drugs used for the treatment of HF24. Once fluid retention has resolved, treatment with the diuretic should be maintained to prevent the recurrence of volume overload.
Patients are commonly prescribed a fixed dose of diuretic, but the dose of these drugs should be adjusted periodically. As previously stated, this adjustment can be accomplished by having the patient record his or her weight each day and allowing the patient to make changes in dose if the weight increases or decreases beyond a specified range.
The response to a diuretic is dependent on the concentration of the drug and the time course of its entry into the urine25. Patients with mild HF respond favorably to low doses because diuretics are rapidly absorbed from the bowel and rapidly delivered to the renal tubules. However, as HF advances, the absorption of the drug may be delayed by bowel edema or intestinal hypoperfusion, and the delivery of the drug may be impaired by a
23 Murray MD, Forthofer MM, Bennett SK, et al. Effectiveness of Torsemide and Furosemide in the Treatment of Congestive Heart Failure: Results of a Prospective, Randomized Trial [abstr]. Circulation 1999;100 Suppl 1:300.
24 Cody RJ, Covit AB, Schaer GL, Laragh JH, Sealey JE, Feldschuh J. Sodium and water balance in chronic congestive heart failure. J Clin Invest 1986;77:1441-52.
25 Cody RJ, Kubo SH, Pickworth KK. Diuretic treatment for the sodium retention of congestive heart failure. Arch Intern Med 1994;154:1905-14.