Should Losartan Be Held in AKI?
Yes, losartan should be held when AKI is diagnosed. The FDA label explicitly warns that drugs inhibiting the renin-angiotensin system can cause changes in renal function including acute renal failure, and clinicians should "consider withholding or discontinuing therapy in patients who develop a clinically significant decrease in renal function" 1. Multiple guidelines consistently recommend discontinuing ARBs like losartan as part of initial AKI management 2.
Evidence-Based Rationale
Guideline Consensus
The 2022 AGA guideline on AKI management in cirrhosis explicitly states that when AKI is diagnosed, "angiotensin II receptor blockers" should be among the "nephrotoxic medications" to avoid, and these agents should be held as part of initial management 2. The 2020 KDIGO conference conclusions identify the need for studies on "timing of ACE-I/ARBs discontinuation and re-initiation in AKI/AKD" but acknowledge current practice favors discontinuation 3.
The 2017 ADQI consensus emphasizes that while ACE inhibitors and ARBs have benefits in chronic conditions, "the risk–benefit ratio in patients with AKD might not reflect that observed in routine clinical practice" 4. The guideline notes that hypotension and decreased filtration fraction are "recognized as common adverse effects" that can "cause or exacerbate AKI" 4.
FDA Drug Label Warnings
The losartan FDA label contains explicit warnings about renal function deterioration: "Changes in renal function including acute renal failure can be caused by drugs that inhibit the renin-angiotensin system." It specifically states to "consider withholding or discontinuing therapy in patients who develop a clinically significant decrease in renal function on losartan" 1. Patients at particular risk include those with renal artery stenosis, chronic kidney disease, severe heart failure, or volume depletion 1.
Clinical Evidence
Recent research demonstrates that continuation of RAASi (including ARBs like losartan) during AKI episodes is associated with worse outcomes. A 2025 retrospective study found that RAASi continuation was associated with increased risk of non-recovery (RR 1.727) and failure of full recovery from AKI (RR 1.427) 5. Notably, under-recognition of AKI was the predominant reason (72.9%) for continuing these medications 5.
When to Hold Losartan
Hold losartan immediately when:
- Serum creatinine increases ≥0.3 mg/dL within 48 hours (Stage 1 AKI) 6
- Serum creatinine rises to ≥1.5 times baseline 6
- Urine output <0.5 mL/kg/hr for >6 hours 6
- Any clinically significant decline in renal function occurs 1
High-Risk Scenarios Requiring Extra Vigilance
Losartan poses particular danger in:
- Volume depletion (including diuretic therapy) 1, 7
- Bilateral renal artery stenosis or stenosis in solitary kidney 8, 9, 7
- Severe heart failure 1
- Pre-existing chronic kidney disease 1
- Elderly patients 7
- Concurrent NSAID use 1
Critical Pitfalls to Avoid
Do not assume losartan is safer than ACE inhibitors in AKI. Available evidence shows losartan causes the same negative renal effects as ACE inhibitors 7. The ELITE trial demonstrated a 10.5% incidence of losartan-induced renal dysfunction, identical to captopril 7.
Do not continue losartan hoping for "renal protection" during acute illness. While ARBs provide long-term benefits in chronic conditions, these benefits do not apply during AKI episodes. The mechanisms that reduce glomerular hypertension chronically become harmful when renal perfusion is compromised acutely 4, 10.
Do not delay discontinuation waiting for "severe" AKI. Hold losartan at Stage 1 AKI (creatinine increase ≥0.3 mg/dL), not just when dialysis is imminent 2.
When to Restart Losartan
Restart losartan only after:
- GFR has stabilized 4
- Volume status is optimized 4
- Serum creatinine returns to within 0.3 mg/dL of baseline 2
- Patient is hemodynamically stable without hypotension 4
- Close monitoring of renal function and electrolytes is established 11, 1
The 2021 heart failure guidelines note that re-introduction should occur "when GFR has stabilized and volume status is optimized," with appropriate clinical and laboratory follow-up essential 11.
Monitoring Requirements
When restarting losartan post-AKI:
- Monitor serum creatinine and potassium within 1-2 weeks 1
- Watch for hyperkalemia (common with ARBs) 1
- Assess for hypotension 4
- Consider lower initial doses with gradual titration 11
Special Consideration: Dual RAAS Blockade
The FDA label explicitly warns against dual RAAS blockade (losartan + ACE inhibitor or aliskiren), which increases risks of hypotension, hyperkalemia, and acute kidney injury 1. The VA NEPHRON-D trial demonstrated that combining losartan with lisinopril increased acute kidney injury incidence without additional benefit 1.