Is Losartan contraindicated in acute kidney injury?

Losartan and Acute Kidney Injury: Not Absolutely Contraindicated, But Requires Careful Risk-Benefit Assessment

Losartan is not absolutely contraindicated in acute kidney injury (AKI), but it should generally be discontinued during AKI episodes and only restarted after careful consideration once renal function has stabilized and volume status is optimized. 1

Understanding the Risk-Benefit Ratio

The relationship between ARBs like losartan and AKI is complex and context-dependent:

When to Avoid or Discontinue Losartan in AKI

The ADQI (Acute Disease Quality Initiative) consensus guidelines recommend discontinuing nephrotoxic agents, including ARBs, when:

• An evaluation indicates the drug is a potential cause of AKI/acute kidney disease (AKD) 1
• A suitable and less nephrotoxic alternative is available 1
• The drug is considered non-essential 1

Specific High-Risk Scenarios

The FDA label explicitly warns that losartan can cause renal function deterioration, including acute renal failure, particularly in patients whose renal function depends on the renin-angiotensin system: 2

• Patients with renal artery stenosis (especially bilateral or in a solitary kidney) 2, 3
• Severe congestive heart failure 2, 3
• Volume or salt depletion 2
• Chronic kidney disease 2

In cirrhotic patients with AKI, ACE inhibitors and ARBs should be avoided as nephrotoxic medications. 1

The Evidence Paradox: Stopping vs. Continuing

A critical nuance exists in the literature that complicates simple recommendations:

Despite routine recommendations to stop ARBs during intercurrent illness, sparse evidence supports this practice. 1 In fact, two studies demonstrated increased 30-day mortality when ACE inhibitors and ARBs were not restarted after surgery, possibly from hypertensive rebound leading to acute cardiac decompensation. 1

The VA NEPHRON-D trial provides important safety data: Dual blockade with losartan plus lisinopril increased AKI incidence (12.2 vs 6.7 per 100 patient-years), but paradoxically, patients who developed AKI on combination therapy had better recovery rates (75.9% vs 66.3%), lower 30-day mortality (4.7% vs 15.0%), and lower risk of progression compared to monotherapy. 4

Practical Management Algorithm

During Active AKI:

1. Discontinue losartan if: 1, 2

   • It is identified as a potential causative agent
   • The patient has volume depletion or hypotension
   • Renal function is acutely deteriorating
   • The patient has bilateral renal artery stenosis or severe heart failure

2. Monitor closely if continuation is deemed essential: 2

   • Check renal function periodically
   • Monitor serum potassium for hyperkalemia 2
   • Assess volume status carefully

After AKI Resolution:

Reintroduction should be considered when: 1

• GFR has stabilized
• Volume status is optimized
• The underlying cause of AKI has been addressed
• Close monitoring can be maintained

Critical Pitfalls to Avoid

Do not combine losartan with ACE inhibitors or aliskiren in patients with diabetes or renal impairment (GFR <60 mL/min), as dual RAS blockade significantly increases AKI risk. 1, 2

Do not assume losartan is safer than ACE inhibitors in patients with renal dysfunction—available evidence suggests equivalent renal toxicity risk. 3

Avoid abrupt permanent discontinuation in patients with chronic heart failure or CKD without considering the mortality risk from inadequate RAS blockade. 1

Correct volume depletion before initiating or restarting losartan to minimize hypotension-related AKI. 2