What medications are used in the Emergency Room (ER) to control blood pressure (BP)?

Emergency Room Medications for Blood Pressure Control

Intravenous antihypertensive medications are the primary agents used in the ER for rapid blood pressure control, with selection based on the specific hypertensive emergency and comorbidities present. 1

Classification of Hypertensive Presentations

Before selecting medication, it's important to distinguish between:

• Hypertensive Emergency: Severe BP elevation (>180/120 mmHg) WITH evidence of new/worsening target organ damage
• Hypertensive Urgency: Severe BP elevation WITHOUT acute target organ damage

First-Line IV Medications by Drug Class

Calcium Channel Blockers (Dihydropyridines)

• Nicardipine: Initial 5 mg/h, increasing every 5 min by 2.5 mg/h to maximum 15 mg/h

  • Contraindicated in advanced aortic stenosis
  • No dose adjustment needed for elderly

• Clevidipine: Initial 1-2 mg/h, doubling every 90s until BP approaches target

  • Maximum dose 32 mg/h; maximum duration 72h
  • Contraindicated with soy/egg allergies and lipid metabolism disorders

Adrenergic Blockers

• Labetalol (combined alpha1 and beta blocker): Initial 0.3-1.0 mg/kg (max 20 mg) slow IV injection every 10 min or 0.4-1.0 mg/kg/h IV infusion

  • Especially useful in hyperadrenergic states
  • Contraindicated in reactive airways disease, heart block, or bradycardia
  • Controls BP more rapidly than nitroglycerin 2

• Esmolol (selective beta1 blocker): Loading dose 500-1000 mcg/kg/min over 1 min followed by 50 mcg/kg/min infusion

  • Short-acting with rapid onset (1-2 min) and short duration (10-30 min)
  • Useful when tight control and quick reversibility are needed

Vasodilators

• Sodium nitroprusside: Initial 0.3-0.5 mcg/kg/min; increase in increments of 0.5 mcg/kg/min

  • Rapid onset but risk of cyanide toxicity with prolonged use
  • Requires intra-arterial BP monitoring to prevent "overshoot"

• Nitroglycerin: Initial 5 mcg/min; increase in increments of 5 mcg/min every 3-5 min to max 20 mcg/min

  • Primarily used for acute coronary syndrome and/or pulmonary edema
  • Do not use in volume-depleted patients

Medication Selection Based on Specific Conditions

Aortic Dissection

• First-line: Esmolol + Nitroprusside or Nitroglycerin
• Alternative: Labetalol or Metoprolol + Nicardipine
• Target: SBP <120 mmHg and heart rate <60 bpm within 20 minutes 1

Acute Coronary Syndrome

• First-line: Nitroglycerin
• Alternative: Labetalol, Urapidil
• Target: SBP <140 mmHg

Acute Pulmonary Edema

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

Acute Stroke

• Ischemic stroke with BP >220/120 mmHg: Labetalol (first-line)
• Ischemic stroke with thrombolytic therapy: Maintain BP <185/110 mmHg
• Hemorrhagic stroke: Target SBP 130-180 mmHg

General BP Reduction Guidelines

• For compelling conditions (aortic dissection, eclampsia, pheochromocytoma): Reduce SBP to <140 mmHg during first hour (and <120 mmHg for aortic dissection)
• For non-compelling conditions: Reduce BP by no more than 25% within first hour, then to 160/100 mmHg within next 2-6 hours, then cautiously to normal over 24-48 hours 1

Common Pitfalls to Avoid

1. Excessive BP reduction: Too rapid or excessive lowering can lead to organ hypoperfusion, especially in chronically hypertensive patients
2. Inappropriate oral therapy: Oral medications are generally discouraged for hypertensive emergencies
3. Overlooking specific contraindications: Each agent has specific contraindications that must be considered
4. Inadequate monitoring: Continuous BP monitoring is essential during treatment of hypertensive emergencies

Remember that hypertensive emergencies require admission to an intensive care unit for continuous monitoring and parenteral therapy, while hypertensive urgencies can typically be managed with oral medications and do not require emergency department referral.