Labetalol

Q: Labetalol is an alpha-1 and ___________ beta-1 blocker? (select one)

A) selective

B) Non-selective

Answer: B

Labetalol is an alpha-1 and non-selective b1 blocker. It can be used in acute aortic dissection, acute myocardial ischemia, acute ischemic stroke/intracerebral bleed, eclampsia/preeclampsia, and hypertensive encephalopathy. It can be given as bolus doses or continuous infusion.

• For bolus doses: 20mg IV can be administrated with an incremental dose of 20-80mg every 10 minutes until the blood pressure (BP) target is achieved
• For continuous infusion: Loading dose 20mg IV is followed by 1-2 mg/min, which can be titrated up until the BP target is achieved

Max dose is 300mg over 24 hours. The onset of action is within 2-5 minutes, and the duration of action is 2-4 hours

Due to its alpha-1 blocking effect, it reduces the SVR without reducing total peripheral blood flow. It should be given with caution in patients with heart failure, sinus bradycardia, and asthma.

#pharmacology

Reference:

MacCarthy EP, Bloomfield SS. Labetalol: a review of its pharmacology, pharmacokinetics, clinical uses and adverse effects. Pharmacotherapy. 1983 Jul-Aug;3(4):193-219. doi: 10.1002/j.1875-9114.1983.tb03252.x. PMID: 6310529.