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Labetalol Hydrochloride (Normodyne, Trandate)

Anesthesia Implications
Classification:
Beta-Blocker
Therapeutic Effects:
Antihypertensive
Time to Onset:

IV: 2-5 min

Time to Peak Effects:

IV: 5-15 minutes

Duration:

2-4 hrs

Primary Considerations:

Heart rate - Labetalol administration does NOT drastically reduce heart rate or result in reflex tachycardia. Blood pressure - Labetalol will produce a dose-dependent decrease in blood pressure. Cerebral blood flow and ICP should remain unaffected. Bronchoconstriction - Labetalol blocks B2 adrenergic receptors, which could contribute to bronchospasm in susceptible patients. As a beta blocker, labetalol will increase resistance to beta agonists (eg albuterol), so be careful with the respiratory patients! Drug interactions - Labetalol will supress/blunt reflex tachycardia seen with administration of nitroglycerin. Hypotensive affects of volatile anesthetics, opoids, etc will be potentiated by labetalol. Cimetidine will increase labetalol bioavailability. OB - Neonatal hypoglycemia and bradycardia risk is increased when the mother is given labetalol at the time of delivery

Contraindications:

Bronchial Asthma Overt cardiac failure 2nd and 3rd degree heart blocks Cardiogenic shock Severe bradycardia

IV push dose:

2.5 - 20 mg. Slow push over 2 minutes

IV infusion dose:

0.5 - 2.0 mg/min. MAX: cumulative dose of 1-4 mg/kg Typically prepared by adding 200 mg of labetalol in 200 ml of normal saline or D5W for a concentration of 1 mg/ml

Method of Action:

Labetalol is a selective, competitive, and alpha 1-adrenergic antagonist. In addition, labetalol is a non-selective, competitive, beta-adrenergic (B1 and B2) blocker. The ratio is 1:7 alpha to beta blockade.

Metabolism:

Hepatic, urinary, fecal

Reference

Omoigui. Sota Omoigui's anesthesia drugs handbook. Fourth edition. 2012.p. 265-267
Bateman. Late Pregnancy Beta-Blocker Exposure and Risks of Neonatal Hypoglycemia and Bradycardia. Pediatrics. 2016.
Miller. Labetalol. StatPearls. 2020.