Lisinopril is a commonly prescribed medication for managing high blood pressure and certain heart conditions. This article explores its relationship with kidney health, detailing its mechanisms and how its effects are monitored.
How Lisinopril Works
Lisinopril belongs to a class of medications called angiotensin-converting enzyme (ACE) inhibitors. It blocks the ACE enzyme, found in the lungs and blood vessel lining. This enzyme normally converts angiotensin I into angiotensin II, a powerful hormone that narrows blood vessels and increases blood pressure.
By inhibiting ACE, lisinopril reduces angiotensin II production, leading to wider, relaxed blood vessels. This vasodilation lowers blood pressure and decreases the heart’s workload. Reduced angiotensin II also leads to less aldosterone secretion, a hormone that causes the kidneys to retain sodium and water, further lowering blood volume and pressure.
Lisinopril’s Effects on Kidneys
Lisinopril can have both beneficial and adverse effects on kidney function. It protects kidneys in conditions like diabetes and chronic kidney disease (CKD) by reducing pressure within the glomeruli, the tiny blood vessels of the kidneys. It dilates the efferent arteriole, the vessel carrying blood away from the glomerulus. This reduces intraglomerular pressure and can slow kidney damage progression. This also decreases proteinuria, the presence of protein in the urine, a sign of kidney damage.
Conversely, lisinopril can decrease kidney function, especially when treatment begins or in individuals with renal artery stenosis, severe heart failure, or dehydration. It can interfere with the kidneys’ ability to filter blood efficiently, leading to a rise in serum creatinine levels. While a small, initial increase in creatinine (typically 5% to 25%) is often expected and reversible, a significant or sustained decline in kidney function warrants medical attention.
Monitoring Kidney Health
Monitoring kidney function is important when taking lisinopril. Healthcare providers assess kidney health using blood tests, including serum creatinine, blood urea nitrogen (BUN), and estimated glomerular filtration rate (eGFR). Creatinine is a waste product from muscle metabolism, and elevated levels can indicate reduced kidney filtration. BUN also measures waste products in the blood, while eGFR estimates how much blood the kidneys filter per minute, providing a comprehensive view of kidney function.
These tests are usually performed before starting lisinopril, shortly after initiation (often around 5 days to 2 weeks), and then periodically during ongoing treatment. The frequency of monitoring depends on individual risk factors and existing kidney function. Patients should also be aware of symptoms like decreased urine output, swelling in the ankles or feet, or unusual fatigue, and contact their healthcare provider if these occur.
When Lisinopril Use Changes
Lisinopril dosage may need adjustment, or the medication might be paused or discontinued due to kidney concerns. A significant rise in serum creatinine, typically more than 30% above baseline within four weeks of starting or increasing the dose, or a decline in GFR exceeding 30%, may necessitate a change in treatment. Uncontrolled electrolyte imbalances, such as hyperkalemia (high potassium), are also a reason to reconsider lisinopril use, especially if serum potassium exceeds 5.5 mEq/L.
Acute kidney injury or a drop in systolic blood pressure below 90 mmHg can also lead to temporary discontinuation. These decisions are made by a healthcare professional, considering the patient’s overall clinical condition, other medications, and ongoing test results. Open communication between the patient and their doctor about any symptoms or concerns is important for appropriate management of kidney health while on lisinopril.