[Diuretic therapy in acute heart failure]

Diuretics are widely recommended in patients with acute heart failure (AHF). Unfortunately, despite their widespread use, limited data are available from randomized clinical trials to guide clinicians on the appropriate management of diuretic therapy. Loop diuretics are considered the first-line diuretic therapy, especially intravenous furosemide, but the best mode of administration (high-dose versus low-dose and continuous infusion versus bolus) is unclear. When diuretic resistance develops, different therapeutic strategies can be adopted, including combined diuretic therapy with thiazide diuretics and/or aldosterone antagonists. Low or "non-diuretic" doses (25-50mg QD) of aldosterone antagonists have been demonstrated to confer a survival benefit in patients with heart failure and reduced ejection fraction and consequently should be prescribed in all such patients, unless contraindicated by potassium and/or renal function values. There is less evidence on the use of aldosterone antagonists at higher or "diuretic" doses (≥ 100mg QD) but these drugs could be useful in relieving congestive symptoms in combination with furosemide. Thiazide diuretics can also be helpful as they have synergic effects with loop diuretics by inhibiting sodium reabsorption in distal parts of the nephron. The effect of diuretic therapy in AHF should be monitored with careful observation of clinical signs and symptoms of congestion. Serum electrolytes and kidney function should also be monitored during the use of intravenous diuretics.