Antihypertensive Management in Acute Kidney Injury
Hold All ACE Inhibitors, ARBs, and Diuretics Immediately
When AKI is diagnosed, discontinue ACE inhibitors, ARBs, nonselective beta-blockers, and diuretics immediately to prevent further hemodynamic compromise and worsening renal function. 1, 2 These agents directly impair renal autoregulation by blocking angiotensin II receptors or depleting intravascular volume, which decreases glomerular filtration pressure in already compromised kidneys. 2
Blood Pressure Management Strategy in AKI
Step 1: Assess for Hypertensive Emergency vs. Urgency
- Hypertensive emergency = BP >180/120 mmHg WITH acute target organ damage (altered mental status, chest pain, acute pulmonary edema, acute MI, stroke, acute worsening of renal function beyond baseline AKI). 3, 4
- Hypertensive urgency = BP >180/120 mmHg WITHOUT acute target organ damage. 3, 4
If hypertensive emergency: Admit to ICU with continuous arterial line monitoring and initiate IV antihypertensive therapy. 3, 4
If hypertensive urgency: Manage with oral agents as outpatient; do NOT use IV therapy or admit to hospital. 3, 4
First-Line IV Antihypertensives for Hypertensive Emergency with AKI
Nicardipine (Preferred Agent)
Nicardipine is the first-line IV agent for hypertensive emergencies in AKI patients because it maintains renal blood flow, does not increase intracranial pressure, and allows predictable titration without exacerbating bradycardia or heart block. 3, 4, 5
- Start at 5 mg/hr IV infusion
- Increase by 2.5 mg/hr every 15 minutes until target BP reached
- Maximum dose: 15 mg/hr
- Onset: 5–15 minutes; duration: 30–40 minutes
- Reduce mean arterial pressure by 20–25% in the first hour
- Then reduce to ≤160/100 mmHg over 2–6 hours if stable
- Gradually normalize over 24–48 hours
Avoid systolic drops >70 mmHg to prevent cerebral, coronary, or renal ischemia, especially in chronic hypertensives with altered autoregulation. 3, 4
Labetalol (Alternative Agent)
Labetalol is preferred for hypertensive emergency with AKI when there is concurrent tachycardia, aortic dissection, or eclampsia. 3, 4
- 10–20 mg IV bolus over 1–2 minutes
- Repeat or double dose every 10 minutes (max cumulative dose 300 mg)
- OR continuous infusion at 2–8 mg/min
- Reactive airway disease or COPD (beta-2 blockade causes bronchoconstriction)
- Second- or third-degree heart block
- Severe bradycardia
- Decompensated heart failure or acute pulmonary edema
Oral Antihypertensives for Hypertensive Urgency with AKI
If BP >180/120 mmHg WITHOUT acute target organ damage, use oral agents with outpatient follow-up in 2–4 weeks. 3, 4
Preferred Oral Agents:
Extended-release nifedipine 30–60 mg PO (calcium channel blocker with minimal renal hemodynamic effects). 3, 4
Amlodipine 2.5–10 mg daily (dihydropyridine CCB with minimal effects on renal hemodynamics). 2
- Gradual reduction to <160/100 mmHg over 24–48 hours
- Achieve <130/80 mmHg within 3 months
Avoid rapid BP lowering in hypertensive urgency as it may cause cerebral, renal, or coronary ischemia in chronic hypertensives. 3, 4
Agents to AVOID in AKI
ACE Inhibitors and ARBs
Do NOT initiate or continue ACE inhibitors or ARBs during active AKI. 1, 2 These agents block angiotensin II receptors, decreasing glomerular filtration pressure and exacerbating kidney dysfunction. 2
When to consider reintroducing ARBs/ACE inhibitors after AKI resolution: 2
- GFR has stabilized
- Volume status is optimized
- Mean arterial pressure >65 mmHg
- Serum potassium <5.5 mEq/L
- Monitor creatinine and potassium within 1 week of restarting
Loop Diuretics
Hold diuretics during the acute phase of AKI unless there is severe volume overload with pulmonary edema. 1 Loop diuretics may convert oliguric to non-oliguric AKI but do NOT improve survival or renal recovery. 7, 8
If diuretics are needed for volume overload: 2
- Use furosemide in moderate-to-severe AKI
- Thiazide diuretics only effective if GFR >30 mL/min
Hydralazine
Avoid hydralazine as first-line therapy due to unpredictable response, prolonged duration, and risk of reflex tachycardia that can worsen myocardial ischemia. 3, 4, 6 Reserve for eclampsia/preeclampsia only. 3, 4
Sodium Nitroprusside
Use nitroprusside only as last resort due to cyanide toxicity risk, especially with prolonged use (>48–72 hours) or in renal insufficiency. 3, 4 If used, co-administer thiosulfate when infusion ≥4 µg/kg/min or >30 minutes. 3, 4
Fluid Management in AKI with Hypertension
Optimize volume status with isotonic crystalloids (0.9% NaCl or balanced crystalloids) to restore renal perfusion. 1, 9, 10
Avoid hydroxyethyl starch (HES) as it increases risk of AKI and need for renal replacement therapy. 9, 7
Monitor for volume overload: 1
- Use urine output, vital signs, echocardiography, or CVP monitoring
- Excessive albumin use increases risk of pulmonary edema
Vasopressor Support if Hypotensive
If mean arterial pressure <65 mmHg despite fluid resuscitation, initiate vasopressors. 1, 8
Norepinephrine is first-line vasopressor for septic shock with AKI. 1, 8
Vasopressin may be beneficial in less severe septic shock. 8
Critical Monitoring Requirements
- Serum creatinine and electrolytes every 6–12 hours during first 24–48 hours. 4
- Urine output monitoring (oliguria = <0.5 mL/kg/hr for >6 hours). 1, 10
- Avoid nephrotoxic agents: NSAIDs, aminoglycosides, vancomycin, amphotericin B, IV contrast. 1
Post-AKI Blood Pressure Management
After AKI resolution, reintroduce ACE inhibitors or ARBs cautiously if indicated for proteinuria, heart failure, or diabetic nephropathy. 2
Reintroduction criteria: 2
- GFR stabilized
- Volume status optimized
- Serum potassium <5.5 mEq/L
- Monitor renal function and potassium within 1 week
Target BP after AKI recovery: 1
- <130/80 mmHg for patients with albuminuria ≥30 mg/24h
- <140/90 mmHg for patients without albuminuria
Key Pitfalls to Avoid
- Do NOT use IV antihypertensives for hypertensive urgency (no target organ damage). 3, 4
- Do NOT rapidly lower BP in asymptomatic severe hypertension without acute organ damage. 3, 4
- Do NOT continue ACE inhibitors/ARBs during active AKI. 1, 2
- Do NOT use immediate-release nifedipine due to stroke risk. 3, 4
- Do NOT normalize BP acutely in chronic hypertensives (altered autoregulation). 3, 4