What antihypertensive medication is suitable for use in patients with Acute Kidney Injury (AKI)?

From the Guidelines

In patients with acute kidney injury (AKI), calcium channel blockers such as amlodipine (5-10 mg daily) or non-dihydropyridine agents like diltiazem are preferred first-line options as they don't directly affect renal hemodynamics. When managing blood pressure in patients with AKI, it is crucial to prioritize medications that do not further compromise renal function. The use of angiotensin-converting enzyme inhibitors (ACEIs) like lisinopril or angiotensin receptor blockers (ARBs) like losartan should generally be avoided or discontinued temporarily as they can worsen kidney function during acute injury 1. Instead, calcium channel blockers such as amlodipine or non-dihydropyridine agents like diltiazem are recommended as first-line options because they do not directly affect renal hemodynamics, thus reducing the risk of further kidney damage 1. Beta-blockers like metoprolol (25-100 mg twice daily) can also be used safely in patients with AKI, as they do not have a significant adverse effect on renal function 1. For patients requiring multiple agents, careful addition of hydralazine (10-25 mg three to four times daily) or low-dose loop diuretics may be considered if volume status permits, with close monitoring of kidney function and electrolytes 1. Blood pressure targets should be slightly higher than usual (aim for <160/90 mmHg rather than more aggressive targets) to maintain adequate renal perfusion, and medication dosing should be adjusted based on estimated glomerular filtration rate 1. The choice of antihypertensive should be individualized based on the cause of AKI, volume status, and comorbidities, with the goal of maintaining adequate renal perfusion while controlling blood pressure 1. It is also important to consider the potential risks and benefits of each medication, as well as the patient's overall clinical condition, when selecting an antihypertensive agent for use in AKI 1. Key considerations include:

• Avoiding ACEIs and ARBs due to their potential to worsen kidney function
• Using calcium channel blockers as first-line agents due to their neutral effect on renal hemodynamics
• Carefully selecting and dosing additional agents based on patient-specific factors
• Monitoring kidney function, electrolytes, and blood pressure closely to adjust therapy as needed.

From the FDA Drug Label

In hypertensive patients with normal kidneys who are treated with hydrALAZINE, there is evidence of increased renal blood flow and a maintenance of glomerular filtration rate. ... However, as with any antihypertensive agent, hydrALAZINE should be used with caution in patients with advanced renal damage.

Hydralazine (PO) can be used with caution in patients with acute kidney injury, but it is essential to carefully monitor the patient's condition due to the potential risks associated with advanced renal damage 2.

• The medication may increase renal blood flow and maintain glomerular filtration rate in patients with normal kidneys.
• However, it should be used with caution in patients with advanced renal damage.

From the Research

Blood Pressure Management in Acute Kidney Injury

The management of blood pressure in patients with acute kidney injury (AKI) is crucial to prevent further kidney damage and improve outcomes. Several studies have investigated the optimal blood pressure targets and medication use in AKI patients.

Optimal Blood Pressure Targets

• The optimal mean arterial pressure (MAP) target in AKI patients is debated, with some studies suggesting a target of 65-73 mmHg in patients without hypertension and 70-80 mmHg in patients with hypertension 3.
• Diastolic blood pressure (DBP) targets may also vary, with suggested ranges of 50-60 mmHg in patients without hypertension and 54-62 mmHg in patients with hypertension 3.
• However, other studies suggest that crude MAP may not be an adequate target in AKI, and that other parameters such as mean perfusion pressure, diastolic arterial perfusion, and diastolic perfusion pressures may be more important 4.

Medication Use in AKI

• The use of vasopressors, such as catecholamines, vasopressin, and angiotensin II, may be necessary to support blood pressure in AKI patients, but their use is associated with adverse events 5.
• Calcium channel blockers may be used to manage hypertension in AKI patients, but their effectiveness and safety in this population are not well established 6.
• Other medications, such as loop diuretics, may be used to manage fluid overload and hypertension in AKI patients, but their use must be carefully monitored to avoid worsening kidney function 6, 7.

Considerations for Hypertension Management

• Hypertension is prevalent in AKI patients, with a reported prevalence of 70% in one study 7.
• Uncontrolled hypertension may require dialysis initiation, but caution must be exercised to avoid hypotensive episodes during dialysis 7.
• The choice of antihypertensive medication in AKI patients must be individualized, taking into account the underlying cause of AKI, the presence of other comorbidities, and the potential for adverse effects on kidney function 6, 5.