When to restart losartan (angiotensin II receptor antagonist) after acute kidney injury?

From the Guidelines

Losartan can typically be restarted after acute kidney injury once renal function has stabilized and improved, usually after 1-2 weeks of recovery, as supported by the most recent evidence from 2022 1. When considering restarting losartan, it is crucial to begin with a lower dose than previously prescribed, such as 25 mg daily instead of 50 mg, and monitor kidney function closely with blood tests after 1-2 weeks of restarting therapy.

• Gradual dose titration should be based on blood pressure control and kidney function tests.
• Before restarting, ensure the patient is adequately hydrated and avoid concurrent use of other nephrotoxic medications like NSAIDs.
• The decision to restart should consider the original indication for losartan, as the benefits of RAAS blockade for conditions like heart failure, hypertension with proteinuria, or diabetic nephropathy may outweigh risks, as noted in 1. Losartan works by blocking angiotensin II receptors, which reduces intraglomerular pressure.
• While this is beneficial for long-term kidney protection, it can temporarily reduce glomerular filtration rate, especially in volume-depleted states or when renal perfusion is compromised.
• Careful monitoring is essential as some patients may develop hyperkalemia upon restarting therapy. It is also important to note that small elevations in serum creatinine (up to 30% from baseline) with renin-angiotensin system (RAS) blockers, such as losartan, must not be confused with acute kidney injury, as stated in 1.
• An analysis of the Action to Control Cardiovascular Risk in Diabetes Blood Pressure (ACCORD BP) trial demonstrates that those randomized to intensive blood pressure lowering with up to a 30% increase in serum creatinine did not have any increase in mortality or progressive kidney disease 1. Therefore, the benefits of restarting losartan after acute kidney injury often outweigh the risks, especially when considering the long-term protective effects on the kidneys, as supported by the most recent and highest quality evidence from 2022 1.

From the Research

Restarting Losartan after Kidney Injury

• The decision to restart losartan after kidney injury should be based on the individual patient's condition and medical history 2, 3, 4, 5, 6.
• Losartan, an angiotensin-II receptor antagonist, has been shown to retard the progression of advanced renal insufficiency 3.
• The pharmacokinetics of losartan are not significantly altered in patients with renal insufficiency, and dose adjustment is not necessary 4.
• Studies have demonstrated that losartan can be safely administered to patients with advanced renal failure, with no significant differences in effects on renal function, serum potassium levels, or systemic blood pressure between patients with different levels of serum creatinine 5.
• High-dose losartan (150 mg) has been associated with an increased risk of acute rise in serum creatinine and greater long-term reductions in estimated glomerular filtration rate (eGFR), but retains its net clinical benefit and is associated with reduced risk of death or hospitalization for heart failure 6.
• The timing of incident increases in serum creatinine >0.3 mg/dl and clinical outcomes should be considered when restarting losartan after kidney injury 6.
• Patients with advanced renal dysfunction are not precluded from losartan administration, and the effects of losartan on renal function, serum potassium levels, and systemic blood pressure are similar between patients with different levels of serum creatinine 5.