Is enalaprilat (Angiotensin-Converting Enzyme inhibitor) IV suitable for a patient with intracranial hemorrhage and hypertension?

Enalaprilat IV for Intracranial Hemorrhage with Hypertension

Enalaprilat IV is an acceptable option for blood pressure control in patients with intracranial hemorrhage and hypertension, but it should be used with caution due to the risk of precipitous blood pressure drops, and is generally considered a second-line agent after labetalol or nicardipine. 1

Guideline-Recommended Use and Dosing

Enalaprilat is specifically listed in American Heart Association/American Stroke Association guidelines as an intravenous medication that may be considered for blood pressure control in ICH patients. 1

Dosing Protocol

• Initial test dose: 0.625 mg IV push 1
• Subsequent doses: 1.25 to 5 mg IV push every 6 hours 1
• The lower initial test dose is critical because enalaprilat carries a risk of precipitous blood pressure lowering 1

Blood Pressure Targets in ICH

The appropriate use of enalaprilat depends on the patient's presenting blood pressure and clinical scenario:

For SBP >200 mmHg or MAP >150 mmHg

• Consider aggressive blood pressure reduction with continuous IV infusion, monitoring BP every 5 minutes 1
• Enalaprilat's intermittent bolus dosing makes it less ideal than continuous infusions (labetalol, nicardipine) for this scenario 1

For SBP >180 mmHg or MAP >130 mmHg WITHOUT elevated ICP

• Target modest reduction to MAP ~110 mmHg or BP ~160/90 mmHg using intermittent or continuous IV medications 1
• Enalaprilat can be used in this scenario with the intermittent bolus approach 1

For SBP >180 mmHg or MAP >130 mmHg WITH elevated ICP

• Monitor ICP and maintain cerebral perfusion pressure (CPP) 60-80 mmHg 1
• Enalaprilat may increase ICP in patients with intracranial hypertension, making it a less favorable choice 2

Preferred First-Line Alternatives

Labetalol is recommended as the first-line agent for PRN blood pressure control in ICH because it leaves cerebral blood flow relatively intact and does not increase intracranial pressure 3:

• Dosing: 5-20 mg IV bolus every 15 minutes or 2 mg/min continuous infusion 1

Nicardipine is an alternative first-line agent, particularly favored in North America 3:

• Dosing: 5-15 mg/hour IV infusion 1
• Ultra-early intensive BP reduction with nicardipine (≤2 hours from symptom onset) is associated with reduced hematoma growth and improved functional outcome 4

Critical Safety Considerations

Risk of Precipitous BP Drops

• ACE inhibitors like enalaprilat have the potential to cause unpredictable, precipitous drops in blood pressure 1
• Excessive acute drops in systolic BP (>70 mmHg) are associated with acute renal injury and early neurological deterioration 3
• The first test dose should always be 0.625 mg to assess individual response 1

Effect on Intracranial Pressure

• Angiotensin-converting enzyme inhibitors can further increase ICP in patients with existing intracranial hypertension 2
• This makes enalaprilat less suitable for patients with signs of elevated ICP or mass effect 2

Monitoring Requirements

• Continuous arterial line monitoring is essential for patients requiring IV antihypertensives, as automated cuff monitoring is inadequate 3
• Clinically reexamine the patient every 15 minutes during active BP management 1

Target BP Goals Based on Current Evidence

For patients with SBP 150-220 mmHg, acute lowering to 140 mmHg is safe and may improve functional outcomes 3:

• Target systolic BP of 140-160 mmHg, initiated within 2 hours of onset 3
• Acute lowering of systolic BP to <130 mmHg is potentially harmful and should be avoided 3

For patients with SBP >220 mmHg, more cautious BP lowering is required due to higher rates of neurological deterioration and renal adverse events 3

Common Pitfalls to Avoid

1. Never use enalaprilat as a first-line agent without considering labetalol or nicardipine first 3
2. Never skip the 0.625 mg test dose 1
3. Avoid using enalaprilat in patients with suspected elevated ICP 2
4. Do not use venous vasodilators like nitroprusside, as they may worsen ICP and affect hemostasis 3
5. Maintain CPP >60 mmHg at all times to prevent cerebral hypoperfusion 3

When Enalaprilat May Be Appropriate

Enalaprilat can be considered when:

• Labetalol and nicardipine are contraindicated or unavailable 1
• The patient has SBP 180-220 mmHg without evidence of elevated ICP 1
• Intermittent bolus dosing is preferred over continuous infusion 1
• The patient can be monitored with continuous arterial line BP monitoring 3