What is the algorithm for treating a hypertensive emergency?

From the Guidelines

The management of hypertensive emergency requires immediate blood pressure reduction to prevent end-organ damage, with the goal of reducing mean arterial pressure by no more than 25% within the first hour, then to 160/100-110 mmHg within the next 2-6 hours, as recommended by the most recent guidelines 1.

Key Considerations

• First, establish IV access and begin continuous cardiac monitoring.
• Administer a rapidly-acting IV antihypertensive medication, with first-line medications including labetalol, nicardipine, or clevidipine, as suggested by the European Heart Journal study 1.
• For patients with aortic dissection, target a systolic BP of 100-120 mmHg using beta-blockers like esmolol combined with vasodilators, as recommended by the American College of Cardiology/American Heart Association task force on clinical practice guidelines 1.
• In preeclampsia, use labetalol, nicardipine, or hydralazine, and avoid nitroprusside when possible due to cyanide toxicity risk, as noted in the guidelines 1.

Treatment Approach

• Simultaneously, assess for end-organ damage with labs (CBC, electrolytes, BUN/creatinine, urinalysis) and imaging as indicated.
• Identify and treat the underlying cause while transitioning to oral antihypertensives once the patient is stable.
• This controlled approach prevents cerebral hypoperfusion and other complications from overly rapid BP reduction, as emphasized by the guidelines 1.

Medication Options

• Labetalol: 20-80 mg IV bolus every 10 minutes or 0.5-2 mg/min infusion.
• Nicardipine: 5-15 mg/hr infusion.
• Clevidipine: 1-2 mg/hr initially, titrated up to 4-6 mg/hr.
• Esmolol: loading dose 500 μg/kg over 1 minute, then 50-200 μg/kg/min.
• Hydralazine: 5-10 mg IV every 20 minutes.

From the FDA Drug Label

The time course of blood pressure decrease is dependent on the initial rate of infusion and the frequency of dosage adjustment. For a gradual reduction in blood pressure, initiate therapy at a rate of 5 mg/hr. If desired blood pressure reduction is not achieved at this dose, increase the infusion rate by 2.5 mg/hr every 15 minutes up to a maximum of 15 mg/hr, until desired blood pressure reduction is achieved. For more rapid blood pressure reduction, titrate every 5 minutes.

The algorithm for treating hypertensive emergency with nicardipine (IV) involves:

• Initiating therapy at a rate of 5 mg/hr for a gradual reduction in blood pressure
• Increasing the infusion rate by 2.5 mg/hr every 15 minutes up to a maximum of 15 mg/hr until desired blood pressure reduction is achieved
• Titration can be done every 5 minutes for more rapid blood pressure reduction 2

In a clinical pharmacologic study in severe hypertensives, an initial 0.25 mg/kg injection of labetalol HCl, administered to patients in the supine position, decreased blood pressure by an average of 11/7 mmHg. Additional injections of 0.5 mg/kg at 15-minute intervals up to a total cumulative dose of 1.75 mg/kg of labetalol HCl caused further dose-related decreases in blood pressure.

The algorithm for treating hypertensive emergency with labetalol (IV) involves:

• An initial injection of 0.25 mg/kg
• Additional injections of 0.5 mg/kg at 15-minute intervals up to a total cumulative dose of 1.75 mg/kg or more as needed 3

From the Research

Algorithm for Treating Hypertensive Emergency

The treatment of hypertensive emergency requires immediate reduction in blood pressure to prevent or minimize end-organ damage. The following steps can be taken:

• Identify patients with acute end-organ damage, such as cardiac, renal, or cerebral dysfunction, who require immediate treatment with a titratable, short-acting, intravenous antihypertensive agent 4, 5.
• Select an appropriate intravenous antihypertensive agent based on the patient's clinical presentation and comorbidities, such as:
  • Nicardipine, fenoldopam, labetalol, or esmolol for patients with cardiac or renal dysfunction 5, 6.
  • Clevidipine, a third-generation dihydropyridine calcium-channel blocker, for patients with severe hypertension and end-organ damage 6.
• Avoid using sodium nitroprusside, nifedipine, nitroglycerin, and hydralazine as first-line therapies due to their potential toxicities and adverse effects 4, 6, 7.
• Monitor patients closely in an intensive care unit and adjust the antihypertensive agent as needed to achieve a controlled reduction in blood pressure 4, 5.

Key Considerations

• The primary goal of intervention in a hypertensive crisis is to safely reduce blood pressure and prevent or minimize end-organ damage 4, 5.
• The selection of a specific antihypertensive agent should be based on the agent's pharmacology and patient-specific factors, such as comorbidity and the presence of end-organ damage 5, 6.
• Rapid recognition and initiation of therapy are key to minimizing end-organ damage in patients with hypertensive emergency 5.