When are diuretics used in patients with conditions such as hypertension, heart failure, nephrotic syndrome, or acute kidney injury?

When Diuretics Are Used

Diuretics are indicated in four primary clinical scenarios: heart failure with fluid retention, hypertension (as add-on therapy), edema from nephrotic syndrome or cirrhosis, and primary hyperaldosteronism. 1, 2

Heart Failure

Loop diuretics are recommended for all heart failure patients with evidence of fluid retention to relieve congestion and improve symptoms. 3

• Diuretics should be prescribed to patients with current fluid overload and to most patients with prior history of congestion, as few heart failure patients can maintain target weight without diuretic therapy 3
• Loop diuretics (furosemide, bumetanide, torsemide) are the preferred agents, acting at the loop of Henle to provide powerful natriuresis even when renal function is impaired 3
• The initial oral dose for furosemide is 20-40 mg once or twice daily, with a maximum of 600 mg daily; torsemide 10-20 mg once daily (maximum 200 mg); bumetanide 0.5-1.0 mg once or twice daily (maximum 10 mg) 3
• Diuretics must be combined with ACE inhibitors, beta-blockers, and aldosterone antagonists as part of guideline-directed medical therapy—they should never be used in isolation 3

Critical Dosing Principles in Heart Failure

• The dose must be carefully titrated: inappropriately low doses result in persistent fluid retention, while excessively high doses cause volume contraction, hypotension, and renal insufficiency 3
• For acute decompensated heart failure, the initial IV dose should equal or exceed the patient's chronic oral daily dose 3, 4
• Diuretic-naive patients may respond to furosemide 20-40 mg IV, whereas those on chronic diuretics require at least 2-2.5 times their home oral dose 4, 5

When to Hold Diuretics in Heart Failure

Diuretics should be avoided in heart failure patients with hypotension (SBP <85-90 mmHg), signs of hypoperfusion, anuria, severe hyponatremia, or metabolic acidosis. 3, 4, 6

• In patients with acute kidney injury and heart failure, continue aggressive diuretic therapy unless the patient is hypotensive, anuric, or severely hypovolemic, as worsening renal function during decongestion does not indicate tubular injury when adequate diuresis is achieved 4
• Address hypoperfusion with inotropes or vasopressors before resuming diuretics 4
• In severe acidosis, diuretics are unlikely to work and may cause harm—hold them and address the underlying acidosis first 6

Hypertension

Diuretics are indicated as add-on therapy for hypertension when blood pressure is not adequately controlled on other agents, with a target BP <130/80 mmHg. 3, 1, 2

• Thiazide diuretics may be preferred over loop diuretics in hypertensive patients with mild fluid retention due to more persistent antihypertensive effects 3
• Furosemide can be used for hypertension alone or in combination with other antihypertensive agents, though patients inadequately controlled on thiazides will likely not respond to furosemide alone 2
• In hypertensive patients with heart failure and preserved ejection fraction (HFpEF), diuretics control fluid retention and are crucial for the success of other antihypertensive medications 3

Nephrotic Syndrome and Cirrhosis

Diuretics are indicated for edema management in nephrotic syndrome when disease-specific treatment, fluid/sodium restriction, and other diuretics produce inadequate response. 1, 7

• In cirrhosis, diuretics are indicated when edema persists despite fluid and sodium restriction 1
• Loop diuretics are particularly useful in nephrotic syndrome due to their efficacy even with impaired renal function and hypoalbuminemia 7, 8
• Spironolactone may be especially useful when other diuretics have caused hypokalemia, as it increases serum potassium 1

Managing Diuretic Resistance in Nephrotic Syndrome

• Progressively increase loop diuretic doses and/or add a thiazide with a different mechanism of action (e.g., metolazone 2.5 mg once daily, maximum 20 mg) 3
• This combination requires close monitoring for hypokalemia and further decline in glomerular filtration rate 3
• In severe renal dysfunction with refractory fluid retention, continuous veno-venous hemofiltration may become necessary 3

Acute Kidney Injury

Diuretics have no proven benefit in preventing or treating acute kidney injury and should be avoided unless the patient has clear fluid overload with adequate blood pressure. 3

• Loop diuretics may convert oliguric to non-oliguric acute renal failure in some patients, facilitating management, but they do not affect mortality rates 9
• Diuretics should not be used for oliguria in acute kidney injury before ensuring adequate intravascular volume and perfusion 3
• The question of diuretic versus dialysis management for acute kidney injury with severe fluid overload remains unanswered 3

Primary Hyperaldosteronism

Spironolactone is indicated for short-term preoperative treatment of primary hyperaldosteronism and long-term maintenance in patients with aldosterone-producing adenomas who are not surgical candidates or those with bilateral adrenal hyperplasia. 1

• Initial dosing is spironolactone 12.5-25 mg once daily, with a maximum of 50 mg daily (higher doses occasionally used with close monitoring) 3