What are intravenous (IV) antihypertensive medications?

From the Guidelines

Intravenous antihypertensive medications, such as labetalol, nicardipine, and clevidipine, are the primary treatment options for rapid blood pressure control in hypertensive emergencies, with the goal of reducing morbidity, mortality, and improving quality of life.

Key Medications

• Labetalol: Start with 20 mg IV bolus, followed by 20-80 mg every 10 minutes or 1-2 mg/min infusion 1
• Nicardipine: Begin at 5 mg/hr, increase by 2.5 mg/hr every 5-15 minutes, maximum 15 mg/hr 1
• Clevidipine: Start at 1-2 mg/hr, titrate by doubling the dose every 90 seconds until desired BP, maximum 32 mg/hr 1

Implementation

For immediate implementation:

• Establish IV access and continuous BP monitoring
• Have a second-line agent available (e.g., hydralazine or enalaprilat)
• Target a 20-25% reduction in mean arterial pressure within the first hour These medications work quickly to reduce blood pressure by different mechanisms:
• Labetalol: Combined alpha and beta-blocker
• Nicardipine and Clevidipine: Calcium channel blockers
• Hydralazine: Direct vasodilator
• Enalaprilat: ACE inhibitor The choice depends on the patient's comorbidities and the specific hypertensive emergency, as outlined in the 2019 European Heart Journal position document on the management of hypertensive emergencies 1.

Considerations

Rapid titration and close monitoring are essential to avoid excessive BP lowering, which can lead to organ hypoperfusion. It is crucial to consider the patient's comorbidities, such as heart failure, renal disease, or pregnancy, when selecting an intravenous antihypertensive medication, as certain medications may be contraindicated or require dose adjustments 1. In patients with hypertensive encephalopathy, labetalol may be preferred as it leaves cerebral blood flow relatively intact for a given BP reduction compared with nitroprusside, and does not increase intracranial pressure 1. Overall, the selection of an intravenous antihypertensive medication should be based on the individual patient's needs and the specific clinical scenario, with the goal of reducing morbidity, mortality, and improving quality of life.

From the FDA Drug Label

The principal pharmacological action of Nitroglycerin Injection is relaxation of vascular smooth muscle and consequent dilatation of peripheral arteries and veins, especially the latter Dilatation of the veins promotes peripheral pooling of blood and decreases venous return to the heart, thereby reducing left ventricular end-diastolic pressure and pulmonary capillary wedge pressure (preload). Arteriolar relaxation reduces systemic vascular resistance, systolic arterial pressure, and mean arterial pressure (afterload).

TABLE OF CONTENTS FULL PRESCRIBING INFORMATION: CONTENTS* 1 INDICATIONS AND USAGE 1.1 Hypertension

Intravenous (IV) antihypertensive medications are drugs administered through a vein to treat high blood pressure. Examples include:

• Nitroglycerin (IV): used to reduce systolic and diastolic arterial blood pressure by relaxing vascular smooth muscle and dilating peripheral arteries and veins 2
• Nicardipine (IV): used to treat hypertension 3

From the Research

Definition and Purpose of IV Antihypertensive Medications

• IV antihypertensive medications are used to treat hypertensive crises, which are categorized as either hypertensive emergencies or urgencies depending on the degree of blood pressure elevation and presence of end-organ damage 4, 5, 6.
• The primary goal of intervention in a hypertensive crisis is to safely reduce blood pressure, with immediate reduction required only in patients with acute end-organ damage (i.e., hypertensive emergency) 4, 5.

Types of IV Antihypertensive Medications

• Rapid-acting IV antihypertensive agents are available, including:
  • Clevidipine
  • Labetalol
  • Esmolol
  • Fenoldopam
  • Nicardipine
  • Sodium nitroprusside 4, 5
• Newer agents, such as clevidipine and fenoldopam, may hold considerable advantages over other available agents in the management of hypertensive crises 4, 5.
• Sodium nitroprusside is an extremely toxic drug and its use in the treatment of hypertensive emergencies should be avoided 4, 5.

Treatment Approach

• Patients with hypertensive emergencies are best treated in an intensive care unit with titratable IV hypotensive agents 4, 5.
• Hypertensive urgencies may be treated with oral antihypertensive agents to reduce blood pressure to baseline or normal over a period of 24-48 hours 6.
• The selection of antihypertensive medication depends on the clinical presentation of the patient and the threat of end-organ damage resulting from blood pressure elevation 7.