When are Angiotensin-Converting Enzyme inhibitors (ACEi) contraindicated?

Contraindications for ACE Inhibitors

ACE inhibitors are absolutely contraindicated in patients with bilateral renal artery stenosis, angioedema during previous ACE inhibitor therapy, and pregnancy. 1

Absolute Contraindications

• Bilateral renal artery stenosis or unilateral stenosis in a solitary kidney - ACE inhibitors can cause acute renal failure in these patients due to their effect on efferent arteriolar vasodilation 1, 2, 3
• History of angioedema with previous ACE inhibitor use - this reaction can be life-threatening and justifies permanent avoidance of all ACE inhibitors 1
• Pregnancy - ACE inhibitors are teratogenic and contraindicated in pregnant women or those planning to become pregnant 4

Relative Contraindications and Cautions

ACE inhibitors should be used with caution in the following conditions:

• Very low systemic blood pressure (systolic BP <80 mmHg) - these patients may experience further dangerous hypotension 1
• Markedly increased serum creatinine (>3 mg/dL) - risk of worsening renal function 1
• Elevated serum potassium (>5.5 mEq/L) - risk of dangerous hyperkalemia 1
• Severe sodium depletion - can exacerbate hypotension 4
• Collagen vascular disease with renal involvement - increased risk of adverse reactions 4
• Autosomal dominant polycystic kidney disease with massive renal involvement and chronic renal insufficiency - may precipitate acute renal deterioration 5
• Cardiogenic shock - ACE inhibitors should not be initiated in hypotensive patients at immediate risk of cardiogenic shock 1

Monitoring Recommendations

When using ACE inhibitors in patients with risk factors but no absolute contraindications, careful monitoring is essential:

• Renal function monitoring should be performed:

  • Before starting therapy 1
  • 1-2 weeks after each dose increment 1
  • Every 3-6 months during maintenance therapy 1
  • More frequently in patients with existing renal dysfunction or electrolyte disturbances 1
  • When adding medications that may affect renal function (e.g., aldosterone antagonists, ARBs) 1
  • During any hospitalization 1

• Potassium levels should be monitored, especially in patients:

  • Taking potassium supplements 1
  • Taking potassium-sparing diuretics 1
  • With diabetes mellitus 1

Management of Common Adverse Effects

• Cough (occurs in 5-10% of European descent patients, up to 50% in Chinese patients):

  • Rule out pulmonary congestion as a cause 1
  • If not severe, encourage continuation of therapy 1
  • If persistent and troublesome, consider switching to an ARB 1

• Hypotension:

  • May require reduction in diuretic dose 1
  • Consider temporary reduction in ACE inhibitor dose 1

• Renal insufficiency:

  • Consider reducing diuretic dose if possible 1
  • Mild to moderate azotemia may be tolerated to maintain ACE inhibitor therapy 1

• Hyperkalemia:

  • Adjust medications that may contribute (potassium supplements, potassium-sparing diuretics) 1
  • Monitor more closely in diabetic patients 1

ACE inhibitors provide significant benefits for cardiovascular outcomes and mortality in appropriate patients, but careful patient selection and monitoring are essential to avoid serious adverse events in those with contraindications.