What is the immediate treatment for a hypertensive emergency?

Immediate Treatment of Hypertensive Emergency

In adults with hypertensive emergency, admission to an intensive care unit is recommended for continuous monitoring of blood pressure and target organ damage, with immediate administration of parenteral antihypertensive medications such as labetalol, nicardipine, or sodium nitroprusside. 1

Definition and Recognition

Hypertensive emergency is defined as:

• Severe BP elevation (>180/120 mmHg)
• WITH evidence of new or worsening target organ damage
• 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
  • Aortic dissection
  • Acute renal failure
  • Eclampsia

Treatment Approach

Blood Pressure Reduction Goals

The rate and extent of BP reduction depend on the clinical context:

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

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

2. 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 normalize BP over the following 24-48 hours 1

First-Line Intravenous Medications

The choice of medication depends on the specific clinical presentation:

1. Labetalol:

   • Initial dose: 0.3-1.0 mg/kg IV (maximum initial dose 20 mg)
   • Can be repeated every 10 minutes or given as infusion 0.4-1.0 mg/kg/h
   • First-line for most hypertensive emergencies including malignant hypertension, hypertensive encephalopathy, and stroke 1, 2

2. Nicardipine:

   • Initial dose: 5 mg/h, increasing every 5 min by 2.5 mg/h to maximum 15 mg/h
   • Excellent option for most hypertensive emergencies
   • Contraindicated in advanced aortic stenosis 1, 3

3. Sodium Nitroprusside:

   • Initial dose: 0.3-0.5 mcg/kg/min, titrated to maximum 10 mcg/kg/min
   • Rapid onset and offset of action
   • Use with caution due to risk of cyanide toxicity with prolonged use
   • Particularly useful in acute heart failure with pulmonary edema 1, 4

4. Nitroglycerin:

   • Initial dose: 5 mcg/min, increasing in increments of 5 mcg/min every 3-5 min
   • Preferred for hypertensive emergencies with acute coronary syndromes 1

5. Clevidipine:

   • Initial dose: 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 soy or egg allergies 1

Condition-Specific Approaches

1. Malignant hypertension/hypertensive encephalopathy:

   • First-line: Labetalol
   • Alternatives: Nicardipine, sodium nitroprusside
   • Target: MAP reduction of 20-25% within several hours 1

2. Acute ischemic stroke:

   • Generally withhold BP-lowering unless BP >220/120 mmHg
   • If thrombolytic therapy planned, maintain BP <185/110 mmHg
   • First-line: Labetalol
   • Target: MAP reduction of 15% 1, 5

3. Acute hemorrhagic stroke:

   • First-line: Labetalol
   • Target: SBP 130-180 mmHg 1

4. Acute coronary event:

   • First-line: Nitroglycerin
   • Alternatives: Labetalol, urapidil
   • Target: SBP <140 mmHg 1

5. Acute cardiogenic pulmonary edema:

   • First-line: Nitroprusside or nitroglycerin (with loop diuretic)
   • Target: SBP <140 mmHg 1

6. Acute aortic dissection:

   • First-line: Esmolol and nitroprusside or nitroglycerin
   • Target: SBP <120 mmHg and heart rate <60 bpm 1

7. Eclampsia/severe preeclampsia:

   • First-line: Labetalol or nicardipine with magnesium sulfate
   • Target: SBP <160 mmHg and DBP <105 mmHg 1

Important Caveats

• Oral therapy is generally discouraged for hypertensive emergencies 1
• Avoid excessive BP reduction which can lead to organ hypoperfusion, ischemic stroke, and death 5
• The actual BP level may not be as important as the rate of BP rise; patients with chronic hypertension often tolerate higher BP levels than previously normotensive individuals 1
• Intra-arterial BP monitoring is recommended for sodium nitroprusside to prevent "overshoot" hypotension 1
• Distinguish between hypertensive emergency (requiring immediate treatment) and hypertensive urgency (severe BP elevation without acute target organ damage, which can be treated more gradually) 5

Transition to Maintenance Therapy

Once BP is stabilized, transition to oral antihypertensive agents should be initiated to allow discontinuation of IV medications. Long-term follow-up is essential to prevent recurrence of hypertensive crisis 5.