Does losartan cause kidney damage?

October 10, 2025 •

3 min read

In a major clinical trial, losartan reduced the incidence of end-stage renal disease by 28% in patients with type 2 diabetes and nephropathy. This raises the question: does losartan cause kidney damage, or is it protective?

Quick Summary

Contrary to causing harm in most patients, losartan is frequently prescribed to protect the kidneys by slowing the progression of diabetic nephropathy and reducing proteinuria. However, it can pose risks in certain situations.

Key Points

Protective Effects: Losartan is generally kidney-protective, especially in patients with hypertension and type 2 diabetes, by slowing the progression of kidney disease.
Mechanism: It works by blocking angiotensin II, a hormone that constricts blood vessels, thus lowering blood pressure and reducing stress on the kidneys.
Risk of Damage: Losartan can cause acute kidney injury in certain high-risk individuals, such as those who are dehydrated, have renal artery stenosis, or take NSAIDs concurrently.
Not a Cause of CKD: Losartan does not cause chronic kidney disease; it is prescribed to slow its progression by reducing proteinuria.
Monitoring is Crucial: Regular monitoring of kidney function (creatinine) and potassium levels is essential for patients on losartan.
Drug Interactions: Combining losartan with NSAIDs (like ibuprofen) or other RAAS inhibitors (like lisinopril) increases the risk of kidney problems.
Reversible Effects: In many cases where losartan causes renal deterioration, the effect is reversible upon stopping the medication.

Understanding Losartan and Its Purpose

Losartan is an angiotensin II receptor blocker (ARB) primarily used to treat high blood pressure (hypertension). It works by blocking the action of angiotensin II, a hormone that constricts blood vessels, leading to relaxed and widened blood vessels and lower blood pressure. This effect is beneficial for cardiovascular health and reduces stress on the kidneys. Losartan is also approved to lower stroke risk in certain patients and manage diabetic kidney disease (nephropathy).

The Protective Role of Losartan on the Kidneys

Losartan often protects the kidneys, particularly for individuals with high blood pressure and type 2 diabetes. By controlling blood pressure, losartan helps reduce the risk of chronic kidney disease (CKD), a common complication of these conditions. A key benefit is the reduction of proteinuria, a sign of kidney damage. The RENAAL study demonstrated that losartan significantly reduced proteinuria by 35% and the risk of developing end-stage renal disease by 28% in patients with type 2 diabetes and nephropathy. This protective effect on the kidneys is a major advantage of losartan and helps slow the decline in kidney function.

When Can Losartan Be Harmful to Kidneys?

While generally protective, losartan can potentially cause or worsen kidney problems, including acute kidney injury (AKI), in specific circumstances. Prolonged use can sometimes affect kidney function, necessitating regular monitoring. Risk factors include dehydration, bilateral renal artery stenosis, severe congestive heart failure, concurrent NSAID use, and dual RAAS blockade. In these cases, renal function deterioration is often reversible upon stopping the medication.

Comparison of Losartan and Other Blood Pressure Medications

Losartan is often compared to ACE inhibitors like lisinopril, as both impact the renin-angiotensin system and offer kidney protection. However, they differ in mechanism and side effects.


Feature	Losartan (ARB)	Lisinopril (ACE Inhibitor)
Mechanism	Blocks angiotensin II receptors.	Inhibits angiotensin II production.
Kidney Protection	Proven to slow diabetic nephropathy.	Offers significant renal protection in diabetics.
Common Side Effect	Dizziness.	Persistent dry cough.
Hyperkalemia Risk	Can increase potassium.	Can increase potassium.
Use in CKD	Effective in slowing progression.	Often first-line due to more data.

Monitoring and Managing Kidney Health on Losartan

Regular monitoring of kidney function and potassium levels is essential for patients on losartan. Blood tests for serum creatinine, eGFR, and potassium are typically performed 1 to 4 weeks after starting or adjusting the dose, periodically during long-term use, and more frequently for individuals with risk factors. Symptoms that could indicate worsening kidney function include decreased urination, swelling, weight gain, fatigue, and shortness of breath.

Conclusion

For most individuals with hypertension and diabetes, losartan is kidney-protective, slowing CKD progression by lowering blood pressure and reducing proteinuria. However, there is a risk of kidney damage in certain patients with specific vulnerabilities like dehydration, renal artery stenosis, or those using NSAIDs concurrently. Safe and effective use of losartan requires careful patient selection and consistent monitoring of kidney function and potassium levels by a healthcare professional.

Disclaimer: This article is for informational purposes only and does not constitute medical advice. Always consult with a qualified healthcare professional before making any decisions about your health or treatment.

{Link: NHS https://www.nhs.uk/medicines/losartan/}

Frequently Asked Questions

Losartan cannot typically reverse existing chronic kidney damage, but it can significantly slow its progression, particularly in patients with type 2 diabetes and nephropathy by reducing proteinuria. Any acute kidney injury caused by the drug is often reversible upon discontinuation.

Signs of kidney problems from losartan can include a decrease in the amount of urine, swelling in the ankles, hands, or feet, unexplained weight gain, weakness, and shortness of breath.

No, it is generally not recommended. Taking nonsteroidal anti-inflammatory drugs (NSAIDs) like ibuprofen with losartan increases the risk of kidney damage, especially in older adults, those who are dehydrated, or those with existing kidney problems.

Losartan is generally considered safe for long-term use and is most effective when taken over a long period. However, because long-term use can sometimes affect kidney function, regular monitoring through blood tests is essential to ensure it remains safe for an individual.

Losartan can cause an increase in serum creatinine levels, which may indicate a decrease in kidney function. In the RENAAL study, losartan reduced the incidence of a doubling of serum creatinine, indicating a long-term protective effect, but short-term increases can occur and require monitoring.

Individuals who are pregnant, have bilateral renal artery stenosis, or are taking aliskiren with diabetes should not take losartan. Caution is also required for those with severe heart failure, liver impairment, or a history of angioedema.

A major difference is their side effect profile. Lisinopril, an ACE inhibitor, is known for causing a persistent dry cough in up to 20% of patients. Losartan, an ARB, has a much lower incidence of this side effect, making it a common alternative for patients who cannot tolerate ACE inhibitors.