What is the treatment for a hypertensive emergency?

Treatment of Hypertensive Emergency

Hypertensive emergencies require immediate reduction of blood pressure with intravenous antihypertensive medications, with the specific agent and target blood pressure determined by the type of end-organ damage present. 1

Definition and Clinical Significance

• Hypertensive emergency: Severe BP elevation (>180/120 mmHg) with evidence of new or worsening target organ damage
• 1-year mortality rate >79% if left untreated
• Examples of target organ damage include:
  • Hypertensive encephalopathy
  • Intracranial hemorrhage
  • Acute ischemic stroke
  • Acute myocardial infarction
  • Acute left ventricular failure with pulmonary edema
  • Unstable angina
  • Dissecting aortic aneurysm
  • Acute renal failure
  • Eclampsia

General Treatment Principles

• Oral therapy is generally discouraged for hypertensive emergencies

• For patients without compelling conditions:

  • Reduce SBP by no more than 25% within the first hour
  • Then, if stable, reduce to 160/100 mmHg within next 2-6 hours
  • Cautiously reduce to normal during the following 24-48 hours 1

• For compelling conditions (aortic dissection, severe preeclampsia/eclampsia, pheochromocytoma crisis):

  • Reduce SBP to <140 mmHg during first hour
  • For aortic dissection, further reduce to <120 mmHg 1

First-Line IV Medications Based on Clinical Presentation

Nicardipine (Calcium Channel Blocker)

• Dosing: Initial 5 mg/h, increasing every 5 min by 2.5 mg/h to maximum 15 mg/h
• Advantages: No dose adjustment needed for elderly, predictable response
• Administration: Slow continuous infusion via central line or large peripheral vein
• Change infusion site every 12 hours if administered via peripheral vein 1, 2

Clevidipine (Calcium Channel Blocker)

• Dosing: Initial 1-2 mg/h, doubling every 90 seconds until BP approaches target
• Maximum dose: 32 mg/h; maximum duration 72 hours
• Contraindicated in patients with soybean/egg allergies or lipid metabolism disorders 1

Labetalol (Combined α- and β-blocker)

• Particularly useful in:
  • Malignant hypertension
  • Hypertensive encephalopathy
  • Acute ischemic stroke
  • Acute hemorrhagic stroke 3
• Preferred for patients with suspected increased intracranial pressure 3

Sodium Nitroprusside

• Dosing: Initial 0.3-0.5 mcg/kg/min; increase in increments of 0.5 mcg/kg/min
• Maximum dose: 10 mcg/kg/min
• Intra-arterial BP monitoring recommended to prevent "overshoot"
• Warning: Cyanide toxicity with prolonged use; keep treatment duration as short as possible 1

Nitroglycerin

• Use only in patients with acute coronary syndrome and/or acute pulmonary edema
• Initial 5 mcg/min; increase in increments of 5 mcg/min every 3-5 min to maximum 20 mcg/min
• Do not use in volume-depleted patients 1

Specific Clinical Scenarios

Acute Coronary Events

• First-line: Nitroglycerin
• Target: SBP <140 mmHg 3

Acute Cardiogenic Pulmonary Edema

• First-line: Nitroprusside or Nitroglycerin (with loop diuretic)
• Target: SBP <140 mmHg 3

Acute Aortic Dissection

• First-line: Esmolol and Nitroprusside or Nitroglycerin
• Target: SBP <120 mmHg and HR <60 bpm 3

Acute Hemorrhagic Stroke

• First-line: Labetalol
• Target: SBP 130-180 mmHg 3

Monitoring and Follow-up

• Continuous monitoring of vital signs
• Check BP every 30 minutes during first 2 hours
• Monitor BUN and creatinine within 2-4 hours to assess renal function
• Monitor urine output and electrolytes regularly
• Invasive hemodynamic monitoring may be necessary in severe cases 3

Potential Pitfalls and Warnings

• Avoid lowering BP too rapidly or aggressively, which can worsen cerebral perfusion
• Avoid medications that could worsen bradycardia in patients with suspected intracranial pathology (e.g., non-dihydropyridine calcium channel blockers)
• Avoid sodium nitroprusside when possible due to toxicity concerns
• Avoid short-acting nifedipine due to unpredictable BP falls 3
• Hydralazine has unpredictable response and prolonged duration of action, making it less desirable for most hypertensive emergencies 1

Transition to Oral Therapy

• Once BP is stabilized, transition to appropriate oral antihypertensive therapy
• For prolonged control, transfer patients to oral medication as soon as their clinical condition permits 2