What are the alternative blood pressure management options for a patient with resistant hypertension, impaired renal function, and intolerance to ACE inhibitors or ARBs, currently on torsemide, diltiazem (Cardizem) ER, and hydralazine?

Management Options for Resistant Hypertension in a Patient with Impaired Renal Function

For a patient with resistant hypertension, GFR of 38, creatinine of 1.4, who cannot take ACE inhibitors or ARBs, and is currently on torsemide, diltiazem ER, and hydralazine, the addition of low-dose spironolactone should be considered as the next therapeutic option, with careful monitoring of potassium and renal function.

Current Medication Assessment

Before adding new medications, let's evaluate the current regimen:

1. Torsemide: Appropriate loop diuretic for patient with reduced GFR
2. Diltiazem ER: Non-dihydropyridine CCB - potentially problematic
3. Hydralazine TID 100mg: Direct vasodilator at high dose

Recommended Medication Changes

Step 1: Optimize Current Therapy

• Replace diltiazem ER with a dihydropyridine CCB (such as amlodipine)
  • Non-dihydropyridine CCBs like diltiazem should be avoided in heart failure due to negative inotropic properties 1
  • Amlodipine has been shown to be safe in patients with heart failure 1

Step 2: Add Mineralocorticoid Receptor Antagonist

• Add spironolactone 12.5-25mg daily with careful monitoring of potassium and renal function
  • Spironolactone is effective for resistant hypertension when added to existing treatment 1
  • Studies show spironolactone can lower BP by an additional 25/12 mmHg in resistant hypertension 1
  • Monitor serum creatinine and potassium regularly due to risk of hyperkalemia, especially with reduced GFR 1

Step 3: If Spironolactone Not Tolerated

• Consider eplerenone as an alternative mineralocorticoid receptor antagonist 1
• Or amiloride as an indirect aldosterone antagonist 1
• Or consider adding a beta-blocker such as bisoprolol 1

Step 4: Additional Options if BP Still Uncontrolled

• Consider alpha-blocker (doxazosin) 1
• Consider centrally acting agent (clonidine) with caution 1

Monitoring Recommendations

1. Monitor serum potassium and creatinine within 1-2 weeks of starting spironolactone and periodically thereafter
2. Assess BP response both in office and with home BP monitoring
3. Monitor for symptoms of hyperkalemia or worsening renal function

Important Considerations and Pitfalls

• Avoid combination of multiple RAS blockers: Never combine ACE inhibitors with ARBs as this increases risk of hyperkalemia and acute kidney injury without additional benefit 1

• Medication adherence: Ensure patient is taking all medications as prescribed, as non-adherence is a common cause of resistant hypertension 1

• Sodium restriction: Emphasize dietary sodium restriction as this can significantly improve BP control in resistant hypertension 1

• Dihydropyridine vs non-dihydropyridine CCBs: In patients with heart failure risk, dihydropyridine CCBs (amlodipine, felodipine) are preferred over non-dihydropyridine CCBs (diltiazem, verapamil) 1

• Hydralazine dosing: Current dose is high (100mg TID); consider optimizing dose based on response and side effects. Hydralazine can cause reflex tachycardia and fluid retention 2

The most recent and highest quality evidence supports the addition of spironolactone as the next step in resistant hypertension, even in patients with reduced GFR, with appropriate monitoring of potassium and renal function 1.