Can Lasix (furosemide) and Aldactone (spironolactone) be given at the same time?

Yes, Lasix (furosemide) and Aldactone (spironolactone) can and should be given together

The combination of furosemide and spironolactone is explicitly recommended as standard therapy for both cirrhotic ascites and heart failure, with initial combination therapy often preferred over sequential monotherapy. 1

Recommended Dosing Ratios

The optimal ratio is 100 mg spironolactone to 40 mg furosemide (100:40 ratio), given as a single morning dose. 1 This ratio:

• Maintains adequate serum potassium levels by balancing the hyperkalemic effect of spironolactone against the hypokalemic effect of furosemide 1
• Can be increased simultaneously every 3-5 days while maintaining this ratio if response is inadequate 1
• Maximum doses are typically 400 mg/day spironolactone and 160 mg/day furosemide 1

Clinical Context Matters

For Cirrhotic Ascites:

• Combination therapy is superior to spironolactone monotherapy for recurrent ascites, providing faster control with lower hyperkalemia risk 1
• Aldosterone antagonists are the mainstay; loop diuretics alone as monotherapy are not recommended 1
• Sequential addition is acceptable (start spironolactone, add furosemide if insufficient response or hyperkalemia develops) 1

For Heart Failure:

• Combination therapy with ACE inhibitors requires careful monitoring 1
• Starting doses should be spironolactone 12.5-25 mg with furosemide 20-40 mg 1, 2

Critical Monitoring Requirements

Check potassium and creatinine at 3 days, 1 week, then monthly for the first 3 months 1. Specifically monitor:

• Hyperkalemia risk increases with:

  • Baseline creatinine >1.6 mg/dL or creatinine clearance <50 mL/min 1
  • Baseline potassium >5.0 mEq/L 1
  • Concomitant ACE inhibitors (especially doses ≥10 mg enalapril/lisinopril or ≥75 mg captopril) 1
  • Diabetes mellitus, elderly patients, dehydration 3, 4

• Hypokalemia: Temporarily withhold furosemide if it develops 1

• Hyponatremia: Reduce or stop diuretics if sodium <120-125 mmol/L 1

Important Contraindications

Do not give aldosterone antagonists when: 1

• Creatinine clearance <30 mL/min
• Baseline potassium >5.0 mEq/L
• Patient is taking NSAIDs or COX-2 inhibitors (avoid these) 1

Practical Administration

• Give as single morning dose to maximize compliance 1
• Use oral route only; intravenous furosemide can cause acute kidney injury in cirrhosis 1
• Discontinue potassium supplements or reduce them significantly 1
• Weight loss goals: Maximum 0.5 kg/day without peripheral edema; no limit with edema present 1

Evidence Quality Note

The combination regimen is supported by multiple high-quality guidelines including the Korean Association for the Study of the Liver (2018) 1, American College of Cardiology/American Heart Association (2005) 1, and American Association for the Study of Liver Diseases (2004) 1. Research confirms safety and efficacy when properly monitored 5, 2, 6.