Choosing IV Antihypertensives: Labetalol, Nicardipine, and More

Learn how to select IV antihypertensive agents in emergencies. Compare labetalol, nicardipine, clevidipine, and avoid hydralazine.

2 minute read

You’ll get questions about selecting an IV antihypertensive.

First, confirm the indication. Often an IV med isn’t needed at all, such as for asymptomatic hypertension or “PRN” use. But guide options for hypertensive emergency, very high BP with end organ damage, such as acute kidney injury or ischemic stroke.

NPS-adv

Think of labetalol or nicardipine as your workhorses. Either starts lowering BP in about 5 to 10 min and can be used for most indications. Generally, go with labetalol IV bolus doses for modest BP lowering in the range of 30 mmHg or less.

Start with 5 to 20 mg and double every 10 minutes up to 80 mg/dose if needed. “Labetalol failure” is often due to underdosing.
Consider IV labetalol 300 mg/day the usual max. This is based on how it was studied, not a hard-and-fast rule. But it’s a good threshold to re-examine adding or switching meds.
If you want to slowly load labetalol, consider using an infusion for a few hours then switch to scheduled dosing.
But don’t jump to prolonged infusions of labetalol, it lasts 6 hours or more and accumulation can lead to refractory hypotension. For more aggressive BP lowering with a continuous infusion, use nicardipine as your go-to.

NPS-adv

Decrease the rate once BP hits target. “Overshooting” is common with nicardipine since its duration is 30 minutes or more. For example, include orders to reduce the nicardipine rate to 5 mg/hr once the goal is reached and adjust every 5 to 15 min as needed.

Expect to hear clevidipine touted as a “better nicardipine.” Clevidipine wears off faster, about 10 min after stopping. And max doses require less volume 42 mL/hr for clevidipine compared to up to 150 mL/hr for nicardipine.
But clarify that BP lowering seems similar. And max doses are significantly higher for clevidipine compared to nicardipine.

Avoid hydralazine. It can cause erratic BP lowering, is hard to titrate and has a duration of up to 12 hours.

References

van den Born BH, Lip GYH, Brguljan-Hitij J, et al. ESC Council on hypertension position document on the management of hypertensive emergencies. Eur Heart J Cardiovasc Pharmacother. 2019;5(1):37-46.
Whelton PK, Carey RM. The 2017 Clinical Practice Guideline for High Blood Pressure. JAMA. 2017;318(21):2073-2074.
Watson K, Broscious R, Devabhakthuni S, Noel ZR. Focused Update on Pharmacologic Management of Hypertensive Emergencies. Curr Hypertens Rep. 2018;20(7):56.

This note has been edited and reviewed by the pharmacy doctors on NPS team.