What is the dosing regimen for intravenous (IV) Angiotensin-Converting Enzyme (ACE) inhibitors, such as enalaprilat (vasotec), for managing hypertension?

From the Guidelines

For managing hypertension with IV ACE inhibitors, enalaprilat (Vasotec) is typically administered at an initial dose of 1.25 mg over a 5-min period, with doses that can be increased up to 5 mg every 6 h as needed to achieve BP target.

Key Considerations

• The dosing regimen is based on the most recent guidelines from the American College of Cardiology/American Heart Association Task Force on Clinical Practice Guidelines, as outlined in the 2017 ACC/AHA/AAPA/ABC/ACPM/AGS/APhA/ASH/ASPC/NMA/PCNA guideline for the prevention, detection, evaluation, and management of high blood pressure in adults 1.
• The initial dose of 1.25 mg can be titrated upward based on blood pressure response, with a maximum dose of 5 mg every 6 hours.
• Before administration, blood pressure should be closely monitored, and the patient should be adequately hydrated to prevent excessive hypotension.
• IV enalaprilat is particularly useful in hypertensive emergencies when oral medications cannot be used or when rapid blood pressure control is needed.
• Caution is warranted in patients with renal impairment, where dose reduction may be necessary.

Mechanism of Action and Side Effects

• The medication works by inhibiting the conversion of angiotensin I to angiotensin II, thereby reducing peripheral vascular resistance and blood pressure.
• Common side effects include hypotension, headache, and dizziness, and contraindications include pregnancy, history of angioedema with ACE inhibitors, and bilateral renal artery stenosis.

Comparison with Other Guidelines

• While other guidelines, such as the 2007 update from the American Heart Association/American Stroke Association Stroke Council, may recommend different dosing regimens for enalaprilat, the most recent and highest-quality evidence supports the dosing regimen outlined in the 2017 ACC/AHA/AAPA/ABC/ACPM/AGS/APhA/ASH/ASPC/NMA/PCNA guideline 1.

From the FDA Drug Label

DOSAGE AND ADMINISTRATION The usual dosage range of enalapril is 10 to 40 mg per day administered in a single or two divided doses

• The provided drug label does not specify the dosing regimen for intravenous (IV) Angiotensin-Converting Enzyme (ACE) inhibitors, such as enalaprilat (vasotec), for managing hypertension. The FDA drug label does not answer the question.

From the Research

Dosing Regimen for IV ACE Inhibitors

The dosing regimen for intravenous (IV) Angiotensin-Converting Enzyme (ACE) inhibitors, such as enalaprilat (Vasotec), for managing hypertension is as follows:

• The recommended initial dose of enalaprilat is 0.625 mg, as doses above this do not alter response rates or the magnitude of blood pressure reduction 2
• Enalaprilat can be administered intravenously in doses of 0.625,1.25,2.5, and 5 mg, with response rates ranging from 59% to 67% 2
• In moderate and severe systemic hypertension, enalaprilat has been compared to placebo and furosemide, with significant reductions in diastolic blood pressure observed in the enalaprilat group 3
• The cardiopulmonary actions of intravenously administered enalaprilat in trauma patients have been studied, with a decrease in mean arterial pressure (MAP) of > 15% within 30 minutes after injection observed in 17 of 20 patients 4
• In Indian patients with grade III essential hypertension, intravenous enalaprilat (1.25 mg) has been shown to be effective, safe, and well-tolerated, with a peak reduction in blood pressure noted at 4 hours 5

Key Findings

• Enalaprilat is a safe and effective antihypertensive drug for the treatment of hypertensive crisis 2
• The most frequent adverse effect limiting ACE inhibitor therapy is cough 6
• Enalaprilat has been shown to be at least as effective as other established and newer ACE inhibitors, and members of other antihypertensive drug classes 6
• Intravenous enalaprilat can be used to manage severe hypertension in patients requiring an emergency reduction in blood pressure 5