What antihypertensive medication can be given to a patient with severely elevated blood pressure (hypertension) and bradycardia, who is allergic to hydralazine?

Immediate Management: Use Amlodipine or Labetalol

Given the severe hypertension (198/98) with bradycardia (HR 55) and hydralazine allergy, amlodipine is the recommended calcium channel blocker for blood pressure control, as it does not worsen heart rate and is specifically endorsed for hypertensive patients. 1

Why Amlodipine is the Optimal Choice

• Amlodipine is specifically recommended by the European Society of Cardiology for persistent hypertension when standard therapy fails, with Level A evidence supporting its use 1
• Unlike non-dihydropyridine calcium channel blockers (diltiazem, verapamil), amlodipine does not cause bradycardia or negative inotropy, making it safe with a heart rate of 55 1
• The drug provides predictable, gradual blood pressure reduction without reflex tachycardia 1

Alternative: Intravenous Labetalol

• If immediate IV therapy is needed, labetalol produces prompt, controlled blood pressure reduction and is a promising alternative to sodium nitroprusside 2
• However, labetalol's beta-blocking properties could theoretically worsen bradycardia, though its alpha-blocking effects often balance this 2
• Monitor heart rate closely if using labetalol given the baseline bradycardia of 55 2

Why NOT Other Agents

Avoid these medications in this clinical scenario:

• Hydralazine is contraindicated due to documented allergy 1
• Diltiazem and verapamil are contraindicated - these non-dihydropyridine calcium channel blockers cause bradycardia and negative inotropy 1
• Moxonidine is contraindicated - associated with increased mortality 1
• Alpha-adrenoceptor antagonists are not recommended - cause neurohumoral activation and fluid retention 1
• Beta-blockers alone would worsen the existing bradycardia 1

Stepwise Approach to This Patient

Step 1: Assess for hypertensive emergency

• Check for end-organ damage (encephalopathy, acute coronary syndrome, pulmonary edema, acute kidney injury) 2
• If present, this requires IV therapy with goal of 15-25% mean BP reduction 3

Step 2: If no end-organ damage (hypertensive urgency)

• Start oral amlodipine 5-10 mg 1
• Target BP <130/80 mmHg gradually over 24-48 hours 4

Step 3: If IV therapy is required

• Use IV labetalol with continuous heart rate monitoring 2
• Alternative: sodium nitroprusside (traditional agent of choice) 2
• Avoid IV hydralazine - causes unpredictable BP responses, reflex tachycardia, and prolonged duration of action (2-4 hours) 3, 5

Critical Monitoring Parameters

• Hold antihypertensives if diastolic BP falls below 60 mmHg to prevent coronary hypoperfusion 6, 3
• Monitor heart rate continuously - target should remain >50 bpm 1
• Reassess BP every 15-30 minutes initially if using IV agents 3

Common Pitfall to Avoid

The biggest mistake would be using IV hydralazine despite the allergy or choosing diltiazem/verapamil which would dangerously worsen the bradycardia. 1, 5 Hydralazine is frequently misused in hospitalized patients for non-urgent hypertension, causing unpredictable BP changes and hypotension in 11-18% of cases 5