II. Indications
- Blood Pressure Management in Pregnancy
-
Refractory Hypertension
- Effective outpatient agent in oral form patients with Refractory Hypertension
-
Hypertensive Emergency
- Labetalol is a preferred agent when compared with Hydaralazine and Clonidine
-
Nicardipine and Clevidipine have replaced intravenous Labetalol for Hypertensive Emergency
- Labetalol is difficult to achieve Blood Pressure control in Hypertensive Crisis despite titration
- Labetalol is short acting
III. Contraindications
IV. Pharmacokinetics
- Not lipophilic
- Hepatic metabolism
-
Bioavailability 20 to 40%
- Well absorbed but high first-pass hepatic metabolism
- Bioavailability increased when taken with food
V. Mechanism
- Not Cardioselective
- Primary activity is as a negative inotrope
- Chronotropic effect is mild
- 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
VI. Dosing: Adults
- Adjust dose in liver and renal Impairment
- Oral
- 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
VII. 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
VIII. Adverse Effects
- May worsen acute exacerbations of Congestive Heart Failure
- Fatigue
- Erectile Dysfunction
- Orthostatic Hypotension
IX. Drug Interactions
- Systemic Beta Agonists
- Labetalol blocks bronchodilation
X. Safety
- Pregnancy Category C
- Safe in Lactation
XI. Resources
- Labetalol Injection (DailyMed)
- Labetalol Tablet (DailyMed)
XII. References
- (2019) Presc Lett, Resource #350503, Comparison of Oral Beta Blockers
- Olson (2020) Clinical Pharmacology, MedMaster, Miami, p. 66
- Hamilton (2020) Tarascon Pocket Pharmacopeia, Jones and Bartlett, accessed on IOS, 4/9/2021
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Related Studies
| labetalol (on 12/21/2022 at Medicaid.Gov Survey of pharmacy drug pricing) | ||
| LABETALOL HCL 100 MG TABLET | Generic | $0.12 each |
| LABETALOL HCL 200 MG TABLET | Generic | $0.16 each |
| LABETALOL HCL 300 MG TABLET | Generic | $0.21 each |