What is the next step for a patient with Acute Kidney Injury (AKI) and elevated blood pressure despite being on amlodipine (calcium channel blocker) 10 mg?

Management of Elevated Blood Pressure in AKI Despite Amlodipine 10 mg

Add an ACE inhibitor (such as perindopril 2 mg daily) or ARB (such as losartan 50 mg daily) as the next step, provided the patient is hemodynamically stable and not at risk for volume depletion. 1

Stepwise Approach to Blood Pressure Management

Step 1: Assess Current Clinical Status

Before adding medications, verify the following:

• Hold diuretics temporarily if the patient shows signs of volume depletion, as AKI patients are at high risk for hemodynamic instability 1
• Confirm hemodynamic stability - avoid aggressive BP lowering if systolic BP <180 mmHg or diastolic BP <110 mmHg, as excessive control can worsen renal perfusion 2
• Check serum potassium before initiating RAAS blockade, as hyperkalemia risk increases in AKI 1
• Evaluate volume status through physical examination, urine output monitoring, and when available, echocardiography or CVP 1

Step 2: Add RAAS Inhibitor (ACE Inhibitor or ARB)

The preferred second-line agent is an ACE inhibitor or ARB 1:

• Start perindopril 2 mg daily or losartan 50 mg daily 1
• These agents provide renoprotective effects beyond BP control in CKD and are first-line for hypertension with kidney disease 1
• Monitor serum creatinine closely - an increase up to 20% from baseline is acceptable and represents hemodynamic adjustment rather than drug toxicity 1
• Avoid combining ACE inhibitors with ARBs, as this increases risks of hyperkalemia and acute kidney injury without additional benefit for BP control alone 1

Step 3: If BP Remains Elevated, Add a Thiazide-Like Diuretic

If hypertension persists despite amlodipine plus ACE inhibitor/ARB, add indapamide 2.5 mg daily 1:

• Thiazide-like diuretics (chlorthalidone or indapamide) are effective even in moderate CKD 1
• In advanced AKI with eGFR <30 mL/min/1.73 m², consider switching to or combining with a loop diuretic (furosemide 20-80 mg twice daily) for better efficacy 1
• Monitor for electrolyte abnormalities, particularly hypokalemia and hyponatremia 1

Step 4: Consider Additional Agents for Resistant Hypertension

If BP control remains inadequate on three agents, consider 1:

• Low-dose spironolactone (25 mg daily) if serum potassium <4.5 mmol/L and eGFR permits 1
• Hydralazine as an alternative vasodilator 1
• Referral to nephrology or hypertension specialist if BP ≥160/100 mmHg persists on three or more agents 1

Critical Considerations Specific to AKI

Medication Safety in AKI

Amlodipine is generally safe in AKI and does not require dose adjustment 3, 4, 5:

• The current 10 mg dose is appropriate and does not accumulate significantly in renal dysfunction 5
• Amlodipine may actually have renoprotective effects by improving renal blood flow through afferent arteriolar dilation 1, 4
• However, higher doses (10 mg vs 5 mg) are associated with increased risk of renal complications and fluid/electrolyte disorders 2

Avoid Excessive BP Reduction

Target BP should be <160/100 mmHg rather than aggressive normalization 1, 6:

• Overly aggressive BP lowering in AKI can reduce renal perfusion pressure and worsen kidney injury 2
• Hypertension is present in approximately 70% of AKI patients, with higher prevalence in renal and post-renal causes 6
• Dialyzed AKI patients typically have higher BP and require more antihypertensive medications 6

"Sick Day Rules" Education

Counsel the patient to hold ACE inhibitor/ARB and diuretics during intercurrent illness 1:

• Stop these medications if experiencing vomiting, diarrhea, excessive sweating, or inadequate fluid intake 1
• This prevents hemodynamic AKI from volume depletion superimposed on existing kidney injury 1

Medications to Avoid in AKI

Do not use the following agents 1:

• Moxonidine - associated with increased mortality in heart failure and should be avoided 1
• Alpha-adrenoceptor antagonists - cause neurohumoral activation, fluid retention, and worsening outcomes 1
• Non-dihydropyridine calcium channel blockers (diltiazem, verapamil) - negatively inotropic and not recommended if heart failure is present 1
• NSAIDs - nephrotoxic and should be discontinued immediately 1

Monitoring Parameters

Reassess within 2-4 weeks after medication adjustment 1:

• Measure serum creatinine, potassium, and BUN 1
• Evaluate BP response and volume status 1
• Adjust doses based on response, tolerating creatinine increases up to 20% with RAAS inhibitors 1