What is the first line diuretic for Congestive Heart Failure (CHF)?

Loop Diuretics Are the First-Line Diuretic Choice for Congestive Heart Failure

Loop diuretics are the preferred first-line diuretic agents for use in most patients with congestive heart failure (CHF), with furosemide being the most commonly used option. 1, 2

Rationale for Loop Diuretics in CHF

• Loop diuretics are recommended in patients with heart failure with reduced ejection fraction (HFrEF) who have evidence of fluid retention to improve symptoms 1
• They work by inhibiting reabsorption of sodium and chloride at the loop of Henle, providing more potent diuresis than other diuretic classes 2
• The primary goal of diuretic therapy is to eliminate clinical evidence of fluid retention using the lowest effective dose possible 1, 2
• While diuretics effectively relieve congestive symptoms, they have not been definitively shown to reduce mortality (unlike other heart failure medications such as ACE inhibitors, ARBs, beta-blockers, and aldosterone antagonists) 1, 3

Specific Loop Diuretic Options

• Furosemide (20-40 mg once or twice daily initially, maximum 600 mg daily) is the most commonly prescribed loop diuretic 1, 2, 4
• Bumetanide (0.5-1.0 mg once or twice daily, maximum 10 mg daily) has higher oral bioavailability than furosemide 1
• Torsemide (10-20 mg once daily, maximum 200 mg daily) has longer duration of action (12-16 hours vs. 6-8 hours for furosemide) and nearly complete bioavailability 1, 5, 6
• Some evidence suggests torsemide may be superior to furosemide in reducing cardiovascular death or unplanned hospitalization for CHF 6

Clinical Approach to Diuretic Therapy

• Start with low doses in outpatients and gradually increase until urine output increases and weight decreases (typically 0.5-1.0 kg daily) 1, 2
• In patients with severe edema, furosemide may be most efficiently administered on 2-4 consecutive days each week 4
• For maintenance therapy, use the lowest effective dose to maintain euvolemia 1, 2
• Always combine diuretics with other guideline-directed medical therapy (GDMT) that reduces hospitalizations and prolongs survival 1

Managing Diuretic Resistance

• Patients may become unresponsive to high doses of diuretics due to:
  • High dietary sodium intake 1, 2
  • Use of NSAIDs 1, 2
  • Significant impairment of renal function or perfusion 1, 2
• Strategies to overcome diuretic resistance include:
  • Escalation of loop diuretic dose 1
  • Intravenous administration (bolus or continuous infusion) 1, 7
  • Addition of a thiazide diuretic (sequential nephron blockade) 1

Role of Other Diuretic Classes

• Thiazide diuretics may be considered in patients with hypertension and CHF with mild fluid retention 1, 2
• Metolazone or chlorothiazide can be added to loop diuretics in patients with refractory edema unresponsive to loop diuretics alone 1
• Aldosterone receptor antagonists (spironolactone, eplerenone) are primarily used for their mortality benefit rather than diuretic effect 1

Monitoring Considerations

• Monitor for electrolyte imbalances, especially when using high doses or combination diuretic therapy 1, 2
• When doses exceeding 80 mg/day of furosemide are given for prolonged periods, careful clinical observation and laboratory monitoring are particularly advisable 4
• In elderly patients, dose selection should be cautious, usually starting at the low end of the dosing range 4