What medication can I order for acute hypertension that won’t lower heart rate, other than hydralazine (hydrochloride)?

Medications for Acute Hypertension Without Heart Rate Reduction

For acute hypertension requiring treatment without lowering heart rate, nicardipine and clevidipine are the preferred intravenous medications as they effectively reduce blood pressure without significant effects on heart rate. 1

First-Line Options

Calcium Channel Blockers (Dihydropyridines)

• Nicardipine:

  • Initial dose: 5 mg/h IV
  • Titration: Increase by 2.5 mg/h every 5 minutes
  • Maximum dose: 15 mg/h
  • Advantages: No dose adjustment needed for elderly, minimal effect on heart rate 1
  • Contraindication: Advanced aortic stenosis

• Clevidipine:

  • Initial dose: 1-2 mg/h IV
  • Titration: Double dose every 90 seconds initially, then adjust more gradually
  • Maximum dose: 32 mg/h (maximum duration 72 hours)
  • Advantages: Ultra-short acting, rapid titration, minimal effect on heart rate 2
  • Contraindications: Allergy to soy/egg products, defective lipid metabolism

Direct Vasodilator

• Fenoldopam (Dopamine-receptor1 selective agonist):
  • Initial dose: 0.1-0.3 mcg/kg/min IV
  • Titration: Increase by 0.05-0.1 mcg/kg/min every 15 minutes
  • Maximum rate: 1.6 mcg/kg/min
  • Advantages: Maintains renal perfusion, no reflex tachycardia 1
  • Contraindications: Increased intraocular pressure, sulfite allergy

Condition-Specific Considerations

Acute Renal Failure

• Preferred agents: Clevidipine, fenoldopam, nicardipine 1
• Avoid hydralazine due to unpredictable response and prolonged duration of action

Acute Sympathetic Discharge/Catecholamine Excess

• Preferred agents: Clevidipine, nicardipine, phentolamine 1
• Phentolamine: 5 mg IV bolus, repeat every 10 minutes as needed

Acute Pulmonary Edema

• Preferred agents: Clevidipine, nitroglycerin, nitroprusside 1
• Beta blockers contraindicated

Important Considerations

1. Avoid hydralazine as first-line therapy for most hypertensive emergencies due to:

   • Unpredictable response
   • Prolonged duration of action (2-4 hours)
   • BP begins to decrease within 10-30 minutes after administration 1, 3
   • Not ideal for precise BP control in most acute situations 4

2. Monitoring requirements:

   • Continuous BP monitoring recommended, especially with rapid-acting agents
   • Target reduction: 20-25% of mean arterial pressure within several hours 2
   • Avoid excessive BP reduction which may precipitate organ hypoperfusion

3. Transition to oral therapy:

   • Begin oral antihypertensives 1 hour before discontinuing IV medications 2
   • For nicardipine, administer first oral dose 1 hour prior to discontinuation of infusion

Cautions and Contraindications

• Sodium nitroprusside: Though effective, risk of cyanide toxicity with prolonged use; not recommended as first-line therapy 3, 4
• Hydralazine: Unpredictable response makes it undesirable as first-line agent in most situations; primarily used in eclampsia/preeclampsia 1, 5
• Beta blockers (esmolol, labetalol): Will lower heart rate; avoid if maintaining heart rate is priority 1

Practical Algorithm

1. Assess for specific comorbidities (renal failure, pulmonary edema, catecholamine excess)
2. Select appropriate agent based on comorbidities:
   • No specific comorbidities → Nicardipine or clevidipine
   • Renal impairment → Fenoldopam or clevidipine
   • Catecholamine excess → Phentolamine, nicardipine, or clevidipine
3. Start at lower end of dosing range and titrate to effect
4. Monitor BP continuously during titration
5. Begin transition to oral therapy before discontinuing IV medication

By using dihydropyridine calcium channel blockers (nicardipine or clevidipine) or fenoldopam, you can effectively manage acute hypertension without reducing heart rate, which is not possible with beta blockers or combined alpha/beta blockers like labetalol.