From the Guidelines
The estimated glomerular filtration rate (eGFR) typically falls when starting an angiotensin-converting enzyme inhibitor (ACE inhibitor) or angiotensin receptor blocker (ARB) due to their effects on kidney hemodynamics, with a decrease of about 10-20% within the first few weeks of treatment 1. This initial drop is generally considered functional rather than indicating kidney damage, and is often a sign that the medication is working effectively to reduce pressure within the kidney. The decrease typically stabilizes after 2-4 weeks and is usually not a cause for concern unless it exceeds 30% or is accompanied by significant hyperkalemia or other symptoms 1. Some key points to consider when using ACE inhibitors or ARBs include:
- These medications reduce pressure in the glomeruli by dilating the efferent arterioles more than the afferent arterioles, which decreases intraglomerular pressure 1.
- The hemodynamic change leads to a reduction in filtration pressure and consequently a decrease in eGFR 1.
- For patients with certain conditions like heart failure, chronic kidney disease, or hypertension, this temporary reduction in eGFR is often outweighed by the long-term renoprotective benefits these medications provide by reducing proteinuria and slowing progression of kidney disease 1.
- ACE inhibitors and ARBs should not be discontinued for minor increases in serum creatinine (<30%), in the absence of volume depletion 1.
- The use of ACE inhibitors and ARBs is recommended for patients with albuminuria (urine albumin-to-creatinine ratio [UACR] ≥30 mg/g) to reduce the risk of progressive kidney disease 1.
From the FDA Drug Label
The FDA drug label does not answer the question.
From the Research
Mechanism of eGFR Fall with ACE/ARB Initiation
- The exact mechanism of eGFR fall with the initiation of ACE/ARB is not explicitly stated in the provided studies 2, 3, 4, 5, 6.
- However, it is known that ACE inhibitors and angiotensin receptor blockers (ARBs) act on the renin-angiotensin-aldosterone system, which plays a crucial role in regulating blood pressure and kidney function 2.
- The reduction in eGFR may be due to the decreased angiotensin II levels, which can lead to a decrease in glomerular filtration rate 4.
Effects of ACE/ARB on eGFR
- A study found that ARB (losartan 50 mg) compared to placebo may reduce the eGFR rate of decline (MD 5.00 mL/min/1.73 m2, 95% CI 3.03 to 6.97), but the certainty of the evidence is very low 2.
- Another study found that ACEi or ARB treatment initiation led to lower risk for kidney failure with replacement therapy (KFRT), but the effect on eGFR was not explicitly stated 4.
Clinical Implications
- The use of ACE/ARB in patients with chronic kidney disease (CKD) may require close monitoring of eGFR and kidney function 2, 4.
- The decision to initiate ACE/ARB therapy should be based on individual patient characteristics and clinical judgment, taking into account the potential benefits and risks 3, 5, 6.