Is Losartan (losartan) suitable for managing hypertension when the glomerular filtration rate (GFR) is impaired, specifically at a level of severe impaired renal function?

From the Guidelines

Losartan can be used cautiously for blood pressure control when GFR is 26 ml/min, but requires careful monitoring. Start with a lower dose of 25 mg once daily (rather than the typical 50 mg starting dose) and monitor kidney function, potassium levels, and blood pressure closely 1. Dose adjustments should be made gradually based on clinical response and laboratory values. Losartan may actually provide renoprotective benefits in chronic kidney disease by reducing proteinuria and slowing progression through its angiotensin II receptor blocking effects. However, be vigilant for potential side effects including hyperkalemia, acute kidney injury, and hypotension. If GFR continues to decline or significant hyperkalemia develops (potassium >5.5 mEq/L), the medication may need to be discontinued. Regular monitoring every 1-2 weeks initially, then monthly once stable, is essential. Alternative antihypertensives like calcium channel blockers might be considered if losartan is not tolerated.

Some key considerations when using losartan in patients with reduced GFR include:

• Monitoring for signs of hyperkalemia, such as muscle weakness, palpitations, or arrhythmias 1
• Avoiding concomitant use of other medications that may increase the risk of hyperkalemia, such as potassium-sparing diuretics or other renin-angiotensin-aldosterone system inhibitors 1
• Adjusting the dose of losartan based on the patient's renal function and clinical response 1
• Considering alternative antihypertensive agents, such as calcium channel blockers, if losartan is not tolerated or if the patient experiences adverse effects 1

It is also important to note that the use of losartan in patients with reduced GFR should be individualized and based on the patient's specific clinical needs and circumstances. Regular monitoring and follow-up are essential to ensure the safe and effective use of losartan in these patients.

From the FDA Drug Label

Patients with renal insufficiency have elevated plasma concentrations of losartan and its active metabolite compared to subjects with normal renal function. No dose adjustment is necessary in patients with renal impairment unless a patient with renal impairment is also volume depleted [see DOSAGE AND ADMINISTRATION (2.3), WARNINGS AND PRECAUTIONS (5. 3) and CLINICAL PHARMACOLOGY (12.3)].

Losartan use in patients with low GFR:

• The FDA drug label does not provide a specific recommendation for losartan use in patients with a GFR of 26.
• However, it is stated that patients with renal insufficiency have elevated plasma concentrations of losartan and its active metabolite.
• No dose adjustment is necessary unless the patient is also volume depleted.
• It is essential to monitor renal function periodically in patients with renal impairment.
• Consider withholding or discontinuing therapy if a clinically significant decrease in renal function occurs 2.

From the Research

Losartan for Blood Pressure Management with Low GFR

• Losartan is an angiotensin II receptor antagonist that has been shown to be effective in managing blood pressure in patients with chronic kidney disease (CKD) 3, 4.
• A study published in the Kidney International journal found that losartan treatment was associated with a slower decline in long-term renal function, despite an initial acute fall in estimated glomerular filtration rate (eGFR) 3.
• Another study published in the American Journal of Kidney Diseases found that initiating renin-angiotensin system (RAS) inhibitor therapy, such as losartan, in patients with advanced CKD was associated with a lower risk of kidney replacement therapy compared to calcium channel blockers 4.
• However, it is essential to monitor patients with low GFR for potential adverse effects of losartan, such as hyperkalemia, which can be a significant concern in patients with CKD 5.

Considerations for Losartan Use in Patients with Low GFR

• Losartan has been shown to be effective and safe in patients with hypertension and CKD, including those with low GFR 3, 4, 6.
• The glomerular effects of losartan may be beneficial in patients with CKD, as it can help to reduce proteinuria and slow the progression of renal disease 3, 6.
• However, patients with low GFR should be closely monitored for changes in renal function and electrolyte levels, particularly potassium, when initiating losartan therapy 5.