What intravenous (IV) medications can be used to manage a hypertensive crisis?

Intravenous Medications for Hypertensive Crisis Management

For hypertensive crisis management, the primary intravenous medications include labetalol, nicardipine, clevidipine, nitroprusside, nitroglycerin, esmolol, fenoldopam, hydralazine, phentolamine, and enalaprilat, with selection based on the specific clinical presentation and target organ involvement. 1

First-Line IV Medications by Clinical Presentation

Malignant Hypertension with/without TMA or Acute Renal Failure

• First line: Labetalol
• Alternatives: Nitroprusside, Nicardipine, Urapidil

Hypertensive Encephalopathy

• First line: Labetalol (preferred as it preserves cerebral blood flow)
• Alternatives: Nitroprusside, Nicardipine

Acute Ischemic Stroke with BP >220/120 mmHg

• First line: Labetalol
• Alternatives: Nitroprusside, Nicardipine

Acute Hemorrhagic Stroke with SBP >180 mmHg

• First line: Labetalol
• Alternatives: Urapidil, Nicardipine

Acute Coronary Event

• First line: Nitroglycerin
• Alternatives: Urapidil, Labetalol

Acute Cardiogenic Pulmonary Edema

• First line: Nitroprusside or Nitroglycerin (with loop diuretic)
• Alternatives: Urapidil (with loop diuretic)

Acute Aortic Dissection

• First line: Esmolol and Nitroprusside or Nitroglycerin
• Alternatives: Labetalol or Metoprolol, Nicardipine

Eclampsia and Severe Pre-eclampsia/HELLP

• First line: Labetalol or Nicardipine and Magnesium sulfate

Dosing and Administration Details

Labetalol

• Dosing: 0.25–0.5 mg/kg IV bolus; 2–4 mg/min continuous infusion until goal BP, then 5–20 mg/h
• Onset: 5–10 minutes
• Duration: 3–6 hours
• Contraindications: 2nd/3rd degree AV block, heart failure, asthma, bradycardia
• Side effects: Bronchoconstriction, fetal bradycardia 2

Nicardipine

• Dosing: 5–15 mg/h continuous IV infusion, starting at 5 mg/h, increase every 15–30 min by 2.5 mg
• Onset: 5–15 minutes
• Duration: 30–40 minutes
• Contraindications: Advanced aortic stenosis, liver failure
• Side effects: Headache, reflex tachycardia

Nitroprusside

• Dosing: 0.3–10 μg/kg/min, increase by 0.5 μg/kg/min every 5 min
• Onset: Immediate
• Duration: 1–2 minutes
• Contraindications: Liver/kidney failure (relative)
• Side effects: Cyanide toxicity with prolonged use
• Caution: Should be used for shortest time possible; thiosulfate co-administration for infusion rates ≥4–10 μg/kg/min or duration >30 min

Nitroglycerin

• Dosing: 5–200 μg/min, increase by 5 μg/min every 5 min
• Onset: 1–5 minutes
• Duration: 3–5 minutes
• Best for: Acute coronary syndrome and/or pulmonary edema
• Side effects: Headache, reflex tachycardia

Esmolol

• Dosing: 0.5–1 mg/kg IV bolus; 50–300 μg/kg/min continuous infusion
• Onset: 1–2 minutes
• Duration: 10–30 minutes
• Contraindications: 2nd/3rd degree AV block, heart failure, asthma, bradycardia
• Side effects: Bradycardia

BP Reduction Targets

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

   • Reduce SBP to <140 mmHg during first hour
   • For aortic dissection: Reduce to <120 mmHg

2. Without compelling conditions:

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

Important Considerations

• Monitoring: Continuous BP monitoring is essential, preferably intra-arterial for nitroprusside
• Volume status: Many patients are volume depleted due to pressure natriuresis; IV saline may be needed to correct precipitous BP falls
• Avoid: Rapid or excessive falls in either systolic or diastolic BP
• ICU admission: Recommended for all hypertensive emergencies for continuous monitoring of BP and target organ damage 1

Newer Agents to Consider

• Clevidipine:

  • Dosing: 2 mg/h IV infusion, double every 2 min with 2 mg/h until goal BP
  • Onset: 2-3 minutes
  • Duration: 5-15 minutes
  • Contraindications: Soybean/egg allergies, defective lipid metabolism
  • Advantages: Rapid onset and offset, may reduce mortality compared to nitroprusside 3

• Fenoldopam:

  • Dosing: 0.1 μg/kg/min IV infusion, increase every 15 min by 0.05-0.1 μg/kg/min
  • Onset: 5-15 minutes
  • Duration: 30-60 minutes
  • Advantages: Renal-protective effects

Common Pitfalls to Avoid

1. Avoid sodium nitroprusside when possible due to cyanide toxicity risk, especially with prolonged use or in patients with renal/hepatic dysfunction
2. Avoid oral antihypertensives for hypertensive emergencies
3. Avoid nifedipine (immediate release) due to unpredictable BP reduction
4. Avoid hydralazine as first-line due to unpredictable response and prolonged duration
5. Do not reduce BP too rapidly as it may lead to cerebral, cardiac, or renal hypoperfusion
6. Do not use nitroglycerin in volume-depleted patients

Remember that the choice of agent should be tailored to the specific clinical presentation, with careful consideration of the underlying pathophysiology and target organ involvement.