Comparative Pharmacology
Head-to-head clinical analysis: LABETALOL versus METOPROLOL SUCCINATE.
Peer-Reviewed Evidence
Head-to-head clinical analysis: LABETALOL versus METOPROLOL SUCCINATE.
Labetalol vs METOPROLOL SUCCINATE
Comparing the clinical profiles, pharmacokinetic behaviors, and safety indices of these two therapeutic agents.
Labetalol is a racemic mixture of four stereoisomers, each with distinct activity. It is a non-selective beta-adrenergic antagonist (blocking beta1 and beta2 receptors) and a selective alpha1-adrenergic antagonist. The alpha1 blockade causes vasodilation and reduces peripheral vascular resistance, while beta blockade reduces heart rate and myocardial contractility, leading to decreased blood pressure without significant reflex tachycardia.
Selective beta-1 adrenergic receptor antagonist; reduces heart rate, myocardial contractility, and blood pressure by blocking catecholamine effects at beta-1 receptors. Also suppresses renin release.
Oral: 200-1200 mg/day in 2 divided doses; initial 100 mg twice daily. IV: 20 mg bolus over 2 minutes, may repeat 40 mg at 10-minute intervals. Max cumulative dose: 300 mg.
25 to 100 mg orally once daily, titrated at weekly intervals as tolerated; maximum 400 mg/day
None Documented
None Documented
Clinical Note
moderateLabetalol + Digitoxin
"Labetalol may increase the bradycardic activities of Digitoxin."
Clinical Note
moderateLabetalol + Deslanoside
"Labetalol may increase the bradycardic activities of Deslanoside."
Clinical Note
moderateLabetalol + Acetyldigitoxin
"Labetalol may increase the bradycardic activities of Acetyldigitoxin."
Clinical Note
moderateLabetalol + Ouabain
"Labetalol may increase the bradycardic activities of Ouabain."
6-8 hours (terminal elimination half-life); may be prolonged in hepatic impairment, unchanged in renal impairment.
Terminal elimination half-life: 3-7 hours. Twice-daily dosing (metoprolol succinate) provides stable beta-blockade over 24 hours due to extended-release formulation, not due to half-life.
Renal (55-60% as unchanged drug and metabolites); biliary/fecal (minor, approximately 5-10%); remainder metabolized in liver.
Primarily renal (95% as metabolites, <5% unchanged). Three main metabolites: O-demethylated (active), α-hydroxylated (active), and O-demethylated and α-hydroxylated. Biliary/fecal excretion: <5%.
Category A/B
Category C
Alpha/Beta-Blocker
Beta-Blocker