Management of RAS Inhibitors in Acute Kidney Injury
RAS inhibitors (ACEi/ARBs) should be temporarily discontinued in patients with acute kidney injury until renal function has returned to baseline or stabilized. 1
Assessment of AKI and RAS Inhibitor Management
Initial Management
- Immediately discontinue ACEi/ARBs when AKI is diagnosed
- Assess severity and cause of AKI:
- Volume depletion (dehydration, diuretics, diarrhea, vomiting)
- Hemodynamic compromise (hypotension, heart failure, sepsis)
- Nephrotoxicity (contrast media, NSAIDs)
- Compare baseline and current creatinine levels
Criteria for Discontinuation
- Serum creatinine rise >30% from baseline within 4 weeks of starting or increasing dose 2
- Uncontrolled hyperkalemia (K+ >5.6 mmol/L) despite medical management 2, 1
- Symptomatic hypotension 2, 1
- Uremic symptoms in advanced kidney failure (eGFR <15 ml/min/1.73 m²) 2
Supportive Care During AKI
- Correct volume status - address dehydration if present
- Optimize blood pressure - maintain MAP >65 mmHg
- Discontinue other nephrotoxic medications - especially NSAIDs 1
- Monitor electrolytes - particularly potassium levels
- Treat underlying causes - infection, obstruction, etc.
Managing Hyperkalemia
If hyperkalemia occurs with ACEi/ARB use, consider these measures before discontinuing:
- Review and adjust concurrent medications
- Moderate potassium intake
- Consider diuretics if volume status permits
- Consider sodium bicarbonate for acidosis
- Consider GI cation exchangers (potassium binders) 2
Restarting RAS Inhibitors After AKI Resolution
When to Restart
Restart ACEi/ARBs when:
- Renal function has returned to baseline or stabilized 1
- Volume status is optimized
- Precipitating factors have been corrected
- Blood pressure is adequate (MAP >65 mmHg) 1
How to Restart
- Start at a lower dose than previously used
- Expect a small rise in serum creatinine (10-20% is acceptable) 1
- Monitor renal function and potassium within 2-4 weeks after restarting 2
- Titrate dose gradually while monitoring renal function
Special Considerations
High-Risk Patients
- Elderly patients with CKD are at increased risk of AKI with ACEi use, particularly when dosed inappropriately for their renal function 3
- Critically ill patients have higher incidence of AKI when on RAAS blockers 4
- Patients with bilateral renal artery stenosis should have RAS inhibitors discontinued permanently 1
Dosing Considerations
- For creatinine clearance >30 mL/min: standard dosing
- For creatinine clearance 10-30 mL/min: reduce initial dose by 50%
- For creatinine clearance <10 mL/min: start at 25% of normal dose 1
Long-term Outcomes
Despite short-term risks, restarting ACEi/ARBs after AKI resolution is associated with lower long-term mortality 5. However, there may be a higher risk of hospitalization for renal causes and acute kidney disease 6, 5.
Prevention of Recurrent AKI
- Advise patients to temporarily withhold ACEi/ARBs during acute illness, especially with vomiting, diarrhea, or fever 7
- Consider holding ACEi/ARBs 24-48 hours before major surgery 1
- Avoid concurrent use of NSAIDs and other nephrotoxic medications
- Ensure adequate hydration during illness or procedures with risk of volume depletion
Important Cautions
- Never use ACEi and ARB combinations - this increases risk of AKI and hyperkalemia 2
- Target or above-target dosages of ACEi/ARBs are associated with higher risk of AKI compared to lower doses 7
- Patients on diuretics may need dose adjustment when restarting ACEi/ARBs to prevent volume depletion 2
Following these guidelines will help optimize management of RAS inhibitors in patients with AKI, balancing the short-term risks against the long-term benefits of these medications.