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Labetalol
Aka: Labetalol, Trandate
- See Also
- Beta Blocker
- Alpha Adrenergic Antagonist
- Carvedilol
- Indications
- Refractory Hypertension
- Effective outpatient agent in oral form patients with Refractory Hypertension
- Hypertensive Emergency
- Nicardipine has replaced intravenous Labetalol for Hypertensive Emergency
- Labetalol is difficult to achieve Blood Pressure control in Hypertensive Crisis despite titration
- Labetalol is short acting
- Labetalol is a preferred agent when compared with Hydaralazine and Clonidine
- Contraindications
- Asthma
- Bradycardia
- Pharmacokinetics
- Well absorbed and high first-pass metabolism (liver metabolism)
- Mechanism
- Combination of classes (similar to Carvedilol)
- Lowers Blood Pressure without reflex Tachycardia
- Nonselective Beta Blocker (7 fold more beta than alpha activity)
- Binds vascular (and Bronchial) Smooth Muscle beta receptors
- Decreases Heart Rate, Cardiac Output and Blood Pressure
- Selective Alpha-1 Adrenergic Antagonist (weak compared with beta activity)
- Competitively binds vascular Smooth Muscle alpha-1 Adrenergic Receptors
- Blocks peripheral blood vessel Vasoconstriction
- Primary activity is as a negative inotrope
- Chronotropic effect is mild
- Dosing: Adults
- Adjust dose in liver and renal Impairment
- Oral
- Start: 100 mg orally twice daily
- Target: 200 to 600 mg orally twice daily
- Maximum: 2400 mg/day
- Intravenous Injection
- Start: 20 mg slow IV injection
- Next: 40-80 mg every 10 minutes as needed
- Cummulative Maximum: 200-300 mg
- Intravenous Infusion
- Start 0.5 to 2 mg/min IV up to cummulative maximum of 200-300 mg
- Dosing: Children (Not FDA approved)
- Oral
- Start: 4 mg/kg/day orally divided twice daily
- Maximum: 40 mg/kg/day up to adult maximum of 2400 mg
- Intravenous Infusion
- Dose: 0.3 to 1 mg/kg/dose up to 20 mg slow IV injection up to every 10 minutes
- Cummulative Maximum: 200-300 mg
- Intravenous Infusion
- Start 0.4 to 1 mg/kg/hour IV up to 3 mg/kg/hour
- Adverse Effects
- May worsen acute exacerbations of Congestive Heart Failure
- Fatigue
- Erectile Dysfunction
- Orthostatic Hypotension
-
Drug Interactions
- Systemic Beta Agonists
- Labetalol blocks bronchodilation
- References
- Olson (2020) Clinical Pharmacology, MedMaster, Miami, p. 66
- Hamilton (2020) Tarascon Pocket Pharmacopeia, Jones and Bartlett, accessed on IOS, 4/9/2021