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Role of diuretics in heart failure

Diuretics are used in heart failure because of 
  • Rapid relief of symptoms
  • Controls fluid retention
  • Appropriate use of diuretics is the key element in the success of other drugs
Diuretics used are
Thiazide diuretics
Loop diuretics
Potassium sparing diuretics

Thiazide diuretics 
Useful alone or in combination with other diuretics in chronic mild HF
K+ depletion and metabolic alkalosis can occur
Suited only if GFR >50%of normal

Site of action and potency similar to the thiazides 
Effective in the presence of moderate renal failure
Both metolazone and thiazides potentiate intravenousloop diuretics 

Furosemide, Bumetanide, and torsemide
Useful in all forms of HF, particularly in refractory HF and pulmonary edema.
Effective in patients with hypoalbuminemia, hyponatremia, hypochloremia, and with reductions in glomerular filtration rate
The action may be potentiated by I.V.administration and by the addition of other diuretics

Potassium sparing diuretics

Spironolactone acts by competitive inhibition of aldosterone
Amiloride and triamterene act directly on the distal tubule/collecting duct. 
Most effective with loop and/or thiazide diuretics.
Lower dose of spironolactone (25 mg/d), prolong life in patients with advanced HF.