Overview
DESCRIPTION Labetalol hydrochloride tablets, USP are an adrenergic receptor blocking agent that has both selective alpha 1 -adrenergic and nonselective beta-adrenergic receptor blocking actions in a single substance. Labetalol hydrochloride, USP is a racemate, chemically designated as 2-hydroxy-5-[1-hydroxy-2-[(1-methyl-3-phenylpropyl)amino]ethyl] benzamide monohydrochloride, and it has the...
Mechanism of Action
CLINICAL PHARMACOLOGY Labetalol hydrochloride combines both selective, competitive, alpha 1 -adrenergic blocking and nonselective, competitive, beta-adrenergic blocking activity in a single substance. In man, the ratios of alpha- to beta-blockade have been estimated to be approximately 1:3 and 1:7 following oral and intravenous (IV) administration, respectively. Beta 2 -agonist activity has been demonstrated in animals with minimal beta 1 -agonist (ISA) activity detected. In animals, at doses greater than those required for alpha- or beta-adrenergic blockade, a membrane-stabilizing effect has been demonstrated.
Indications
- INDICATIONS AND USAGE Labetalol hydrochloride tablets USP are indicated in the management of hypertension. Labetalol hydrochloride tablets USP may be used alone or in combination with other antihypertensive agents, especially thiazide and loop diuretics.
Common Doses
- 100 mg
- 200 mg
- 400 mg
- 1200 mg
Dosage
DOSAGE AND ADMINISTRATION DOSAGE MUST BE INDIVIDUALIZED. The recommended initial dosage is 100 mg twice daily whether used alone or added to a diuretic regimen. After 2 or 3 days, using standing blood pressure as an indicator, dosage may be titrated in increments of 100 mg b.i.d.(twice daily) every 2 or 3 days. The usual maintenance dosage of labetalol hydrochloride tablets is between 200 mg and 400 mg twice daily. Since the full antihypertensive effect of labetalol hydrochloride tablets is usually seen within the first 1 to 3 hours of the initial dose or dose increment, the assurance of a...
Contraindications
- CONTRAINDICATIONS Labetalol hydrochloride is contraindicated in bronchial asthma, overt cardiac failure, greater-than-first-degree heart block, cardiogenic shock, severe bradycardia, other conditions associated with severe and prolonged hypotension, and in patients with a history of hypersensitivity to any component of the product [see Warnings] . Beta-blockers, even those with apparent cardioselectivity, should not be used in patients with a history of obstructive airway disease, including asthma.
Side Effects
- ADVERSE REACTIONS Most adverse effects are mild and transient and occur early in the course of treatment. In controlled clinical trials of 3 to 4 months' duration, discontinuation of labetalol hydrochloride due to one or more adverse effects was required in 7% of all patients. In these same trials, other agents with solely beta-blocking activity used in the control groups led to discontinuation in 8% to 10% of patients, and a centrally acting alpha-agonist led to discontinuation in 30% of patients.
Interactions
- No major interactions listed on the FDA label. Always consult a healthcare professional.