From the Guidelines
For a hypertensive emergency not responding to nitroglycerin (NTG), the next step is to administer intravenous (IV) labetalol, as it is the preferred first-line treatment for most hypertensive emergencies, including malignant hypertension, hypertensive encephalopathy, and acute ischemic stroke 1. When considering alternative treatments, nicardipine and nitroprusside can also be used, depending on the specific clinical scenario.
- Labetalol can be given as a 20-80 mg IV bolus every 10 minutes or as a continuous infusion at 0.5-2 mg/min.
- Nicardipine is typically started at 5 mg/hr and titrated up by 2.5 mg/hr every 5-15 minutes to a maximum of 15 mg/hr. The choice between agents depends on the specific clinical scenario - labetalol provides both alpha and beta blockade, while nicardipine is a calcium channel blocker that is particularly effective for cerebrovascular emergencies.
- Continuous blood pressure monitoring is essential during administration, with a goal of reducing mean arterial pressure by no more than 25% in the first hour to avoid organ hypoperfusion, as recommended by the European Heart Journal study 1. It is also important to note that the administration of ACE-inhibitors can be used, but must be started at a very low dose to prevent sudden decreases in BP, and intravenous saline infusion can be used to correct precipitous BP falls if necessary 1.
From the FDA Drug Label
The time course of blood pressure decrease is dependent on the initial rate of infusion and the frequency of dosage adjustment. Nicardipine hydrochloride injection is administered by slow continuous infusion at a concentration of 0. 1 mg/mL. For a gradual reduction in blood pressure, initiate therapy at a rate of 5 mg/hr. If desired blood pressure reduction is not achieved at this dose, increase the infusion rate by 2. 5 mg/hr every 15 minutes up to a maximum of 15 mg/hr, until desired blood pressure reduction is achieved.
The next step in managing a hypertensive emergency that is not responding to nitroglycerin (NTG) is to consider alternative intravenous antihypertensive agents such as nicardipine.
- Initiation of therapy: Start with a rate of 5 mg/hr and titrate every 15 minutes by increasing the infusion rate by 2.5 mg/hr up to a maximum of 15 mg/hr until the desired blood pressure reduction is achieved.
- Monitoring: Closely monitor the patient's blood pressure and adjust the infusion rate as needed to maintain the desired response. 2
From the Research
Next Steps in Managing Hypertensive Emergency
If a hypertensive emergency is not responding to nitroglycerin (NTG), the next steps in management would involve:
- Using alternative rapid-acting intravenous antihypertensive agents, such as labetalol, esmolol, fenoldopam, nicardipine, or clevidipine 3, 4
- Avoiding the use of sodium nitroprusside due to its toxicity 3, 4
- Considering the patient's clinical presentation and the presence of end-organ damage to determine the appropriate therapeutic approach 4, 5
- Aiming to reduce mean arterial pressure by approximately 10% during the first hour and a further 10% to 15% during the next 2 to 4 hours 6, 5
Alternative Therapies
Alternative therapies that may be considered include:
- Esmolol, which is effective in controlling both supraventricular tachyarrhythmias and severe hypertension, but should be avoided in patients with low cardiac output 7
- Nicardipine, which is a potent arteriolar vasodilator without a significant direct depressant effect on myocardium, but should not be used in patients with severe aortic stenosis 7
- Fenoldopam, which is a selective post-synaptic dopaminergic receptor (DA1) agonist and has been shown to be effective in treating severe hypertension with a lower incidence of side effects than sodium nitroprusside 7