Obese patients and labetalol

 Q: Obese patients may require a ______ dose of intravenous labetalol bolus. (select one)

A) higher

B) lower

Answer: A

Beta-blockers are lipophilic and so have a tendency to diffuse into adipose tissues. This may lead to restricted tissue distribution in obese patients. 

Labetalol is a mixed alpha and beta-blocker. It can be used as oral, intravenous (IV) bolus, and continuous infusion. In ICU, the usual bolus dose is 10-20 mg but can be titrated up to 80 mg every 10 minutes to a total dose of 300 mg. The infusion dose is 0.5 to 2 mg/min. 

Obese patients may require higher doses. 

#pharmacology

#hemodynamic

#cardiology

References:

1. Cheymol G, Poirier JM, Carrupt PA, Testa B, Weissenburger J, Levron JC, Snoeck E. Pharmacokinetics of beta-adrenoceptor blockers in obese and normal volunteers. Br J Clin Pharmacol. 1997 Jun;43(6):563-70. doi: 10.1046/j.1365-2125.1997.00609.x. PMID: 9205815; PMCID: PMC2042788. 

2. Yiwen Cui, Ethan A. Litman, Paul Feustal, Johanna Bringley, Asha Rijhsinghani Dosing of labetalol in obese preeclamptic women with severe antepartum hypertension: Poster #517,  American Journal of Obstetrics & Gynecology; VOLUME 220, ISSUE 1, SUPPLEMENT , S346-S347, JANUARY 01, 2019 - DOI:https://doi.org/10.1016/j.ajog.2018.11.539