What PRN (pro re nata, or as needed) order should be given for a patient with severe hypertension (systolic blood pressure of 200 mmHg) and bradycardia (heart rate of 60 beats per minute)?

PRN Order for Severe Hypertension with Bradycardia

For a patient with systolic blood pressure of 200 mmHg and heart rate of 60 bpm, order IV nicardipine as the PRN medication, avoiding beta-blockers and labetalol due to the existing bradycardia.

Clinical Context Assessment

This presentation requires immediate determination of whether acute target organ damage is present, as this distinguishes a hypertensive emergency from hypertensive urgency 1:

• Hypertensive emergency: SBP 200 mmHg with new/worsening organ damage (encephalopathy, stroke, acute coronary syndrome, pulmonary edema, aortic dissection, acute renal failure)
• Hypertensive urgency: SBP 200 mmHg without acute organ damage

The bradycardia (HR 60 bpm) is a critical contraindication to several first-line agents and must guide drug selection 1.

Recommended PRN Medication

First-Line Choice: IV Nicardipine

Nicardipine is the optimal PRN agent for this patient because 1:

• Dosing: Initial 5 mg/h IV infusion, increase every 5-15 minutes by 2.5 mg/h until goal BP reached, maximum 15 mg/h
• Onset: 5-15 minutes
• Duration: 30-40 minutes
• Advantages: Does not worsen bradycardia, predictable dose-response, easily titratable
• Side effects: Headache and reflex tachycardia (beneficial in this bradycardic patient)

Alternative: IV Clevidipine

If nicardipine unavailable 1:

• Dosing: Initial 1-2 mg/h IV, double every 90 seconds until BP approaches target, then increase by less than double every 5-10 minutes; maximum 32 mg/h
• Onset: 2-3 minutes (ultra-short acting)
• Duration: 5-15 minutes

Medications to AVOID

Beta-blockers and labetalol are contraindicated in this patient 1:

• Labetalol: Contraindicated with bradycardia, 2nd/3rd degree AV block, and systolic heart failure 1
• Esmolol: Contraindicated with bradycardia and heart rate <60 bpm 1
• Metoprolol: Contraindicated with bradycardia 1

These agents would further reduce the already low heart rate of 60 bpm, risking hemodynamic compromise.

Blood Pressure Targets

If Hypertensive Emergency (with organ damage) 1:

• General target: Reduce MAP by 20-25% within first hour, then to 160/100 mmHg over next 2-6 hours 1
• Specific exceptions:
  • Aortic dissection: SBP <120 mmHg and HR <60 bpm immediately 1
  • Acute pulmonary edema: SBP <140 mmHg immediately 1
  • Acute coronary syndrome: SBP <140 mmHg immediately 1

If Hypertensive Urgency (no organ damage) 1, 2:

• Reduce BP gradually over 24-48 hours
• Can use oral agents rather than IV
• Avoid precipitous drops that may cause hypoperfusion in chronically hypertensive patients 2

Additional PRN Considerations

Oral Options for Urgency

If this is determined to be hypertensive urgency without acute organ damage 1:

• Oral nifedipine: Immediate-release formulation
• Oral methyldopa: Recommended by 2024 ESC guidelines 1
• Avoid sublingual nifedipine due to unpredictable absorption

Monitoring Requirements

For hypertensive emergency requiring IV therapy 1:

• ICU admission for continuous BP monitoring
• Assess for target organ damage: fundoscopy, ECG, troponins, creatinine, urinalysis, chest X-ray as indicated 1
• Avoid reducing BP to normal acutely—this can cause ischemia in chronically hypertensive patients with altered autoregulation 2

Critical Pitfall

The most common error is using labetalol as first-line in all severe hypertension cases 1. While labetalol is widely recommended for most hypertensive emergencies, the existing bradycardia makes it dangerous in this specific patient. The heart rate of 60 bpm is an absolute contraindication to beta-blockade 1.