From the Guidelines
In a hypertensive emergency, blood pressure should be reduced by no more than 25% within the first hour, as recommended by 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. This controlled reduction is crucial to prevent organ damage from occurring too rapidly. The guideline suggests that for adults without a compelling condition, the systolic blood pressure (SBP) should be reduced by no more than 25% within the first hour, then if stable, to 160/100 mm Hg within the next 2 to 6 hours, and then cautiously to normal during the following 24 to 48 hours 1. Some key points to consider when managing hypertensive emergencies include:
- Continuous monitoring of blood pressure and target organ damage in an intensive care unit setting
- Parenteral administration of an appropriate agent, such as IV labetalol, IV nicardipine, or clevidipine
- Avoiding excessive rapid reduction in blood pressure to prevent cerebral, coronary, or renal hypoperfusion
- Frequent vital sign checks and neurological assessments to ensure organ perfusion is maintained The goal is to balance the need to reduce blood pressure with the risk of causing organ damage due to rapid changes in blood pressure, as supported by the guideline recommendations 1.
From the FDA Drug Label
In other settings (e.g., patients with severe or postoperative hypertension), nicardipine hydrochloride injection (5 to 15 mg/hr) produced dose-dependent decreases in blood pressure. ... The mean time to therapeutic response for postoperative hypertension, defined as greater than or equal to 15% reduction in diastolic or systolic blood pressure, was 12 minutes.
The percentage reduction in blood pressure considered safe in a hypertensive emergency is at least 15% reduction in diastolic or systolic blood pressure, as defined for postoperative hypertension 2.
From the Research
Hypertensive Emergency Management
The management of hypertensive emergencies involves the use of parenteral antihypertensive agents and close monitoring of blood pressure.
- The goal of treatment is to reduce mean arterial pressure by no more than 20% during the first few hours 3.
- A reduction of more than 20% may induce severe ischemic injury in major organs due to chronic adaptation of autoregulation mechanisms 3.
- The choice of antihypertensive agent depends on the patient's clinical status and the presence of target organ damage 4, 5, 6.
Reduction in Blood Pressure
- A safe reduction in blood pressure is considered to be no more than 20% of the initial mean arterial pressure during the first few hours of treatment 3.
- This reduction can help prevent target organ damage and reduce the risk of complications 3.
- The reduction in blood pressure should be achieved gradually, with close monitoring of the patient's clinical status and blood pressure 4, 5, 6, 3, 7.