Congestive heart failure diuretics

Overview
Diuretics reduce circulating volume, improve symptoms and are a mainstay of therapy for congestive heart failure. While thes agents improve symptoms, they have not been associated with a reduction in mortality and are associated with electrolyte imbalances.

Mechanism of Benefit

 * Reduce intravascular volume
 * Lasix reduces preload and relaxes pulmonary venules and thereby reduce the symptoms of pulmonary edema
 * Reduce wall stress
 * Improve left ventricular remodeling
 * Improve symptoms but not improve survival. In fact higher doses of lasix are associated with higher mortality, likely as a results of higher doses being a marker of more severe disease.

Complications

 * Azotemia
 * Hypokalemia
 * Contraction or metabolic alkalosis
 * Elevate neurohormones
 * Thiazide diuretics are associated with hyponatremia

Thiazide Diuretics

 * Inhibit the Na+/Cl- co transporter in the distal convoluted tube.
 * Although thiazide diuretics are effective in mild heart failure they are usually inadequate for the treatment of severe heart failure.
 * Thiazide diuretics have also been associative with hyponatremia.

Loop Diuretics

 * Agents in this class include Furosemide or lasix, bumetanide, ethacrynic acid and torsemide.
 * Inhibit the Na+/K+/Cl- transporter.
 * Fluid retention usually responds best to furosemide (Lasix)
 * If there is no response to the initial dose then it can be increased by at least 50%.
 * The maintenance dose of the diuretics lower than that required to initiate diuresis, and for lasix is usually 10 to 20 mg per day.
 * The patient should be told to return to their physician in the next three to seven days after initiation for further assessment including assessment of their potassium concentration.
 * Weight loss should not exceed 1 to 2 pounds/day.
 * If the patient gains more than two pounds and they are instructed to double the dose of their loop diuretic.
 * Once the baseline weight has been re-established than they can resume their previous status.
 * Higher lasix doses are associated with higher mortality, likely as a surrogate of disease severity rather than part of a causal pathway.
 * Intermittent use of metolazone into dose of 2.5 or 5 mg can be given if the patient is refractory to furosemide Lasix. Metolazone should be given in the inpatient setting.

Potassium Sparing Diuretics

 * The role of potassium sparing diuretics such as spironolactone (Aldactone), amiloride, or triamterene remains the subject of controversy.
 * Spironolactone is currently recommended only as third line therapy for congestive heart failure.
 * These agents inhibit Na reabsorbtion and Potassium secretion in the distal convoluted tubule and cortical collecting duct.
 * Their significant side effect is hyperkalemia.
 * Extreme caution is necessary when adding a potassium sparing agent to the regiment that includes ACE inhibitors particularly when diabetes or renal disease is present because the patient can become hyperkalemic.

==ACC/AHA Guidelines- Diuretics Recommendation == {{cquote|

Class I
1. Diuretics and salt restriction are indicated in patients with current or prior symptoms of heart failure and reduced left ventricular ejection fraction (LVEF) who have evidence of ﬂuid retention. (Level of Evidence: C) }}

Vote on and Suggest Revisions to the Current Guidelines

 * The CHF Living Guidelines: Vote on current recommendations and suggest revisions to the guidelines

Guidelines Resources

 * The ACC/AHA 2005 Guideline Update for the Diagnosis and Management of Chronic Heart Failure in the Adult


 * 2009 focused update: ACCF/AHA Guidelines for the Diagnosis and Management of Heart Failure in Adults: a report of the American College of Cardiology Foundation/American Heart Association Task Force on Practice Guidelines: developed in collaboration with the International Society for Heart and Lung Transplantation