Drug information of Labetalol

Labetalol


Labetalol is a beta-blocker that affects the heart and circulation (blood flow through arteries and veins). Labetalol is used to treat hypertension (high blood pressure).

Mechanism of effect

Labetalol HCl combines both selective, competitive, alpha-1-adrenergic blocking and nonselective, competitive, beta-adrenergic blocking activity in a single substance This causes a decrease in systemic arterial blood pressure and systemic vascular resistance without a substantial reduction in resting heart rate, cardiac output, or stroke volume, apparently because of its combined α- and β-adrenergic blocking activity.

Pharmacodynamic

Labetalol is an selective alpha-1 and non-selective beta adrenergic blocker used to treat high blood pressure.

Pharmacokinetics

Completely absorbed (100%) from the gastrointestinal tract with peak plasma levels occurring 1 to 2 hours after oral administration. The absolute bioavailability of labetalol is increased when administered with food. Protein binding: 50%. Primarily hepatic, undergoes significant first pass metabolism. These metabolites are present in plasma and are excreted in the urine, and via the bile, into the feces. Half life: 6-8 hours.

Dosage

Usual Adult Dose for Hypertensive Emergency Oral: Initial dose: 100 mg orally twice a day whether used alone or added to a diuretic regimen. Maintenance dose: 200 to 400 mg orally twice a day.

Alerts

1-Severe hepatocellular injury, confirmed by rechallenge in at least one case, occurs rarely with Labetalol therapy.
2-Sympathetic stimulation is a vital component supporting circulatory function in congestive heart failure. Beta-blockade carries a potential hazard of further depressing myocardial contractility and precipitating more severe failure.
3-Labetalol can be used with caution in patients with a history of heart failure, Ischemic Heart Disease, Nonallergic Bronchospasm (e.g., chronic bronchitis and emphysema), Pheochromocytoma, Diabetes Mellitus and Hypoglycemia, Major Surgery
4-Caution must be observed when reducing severely elevated blood pressure.

Points of recommendation

1-Routine laboratory tests are ordinarily not required before or after intravenous Labetalol. In patients with concomitant illnesses, such as impaired renal function, appropriate tests should be done to monitor these conditions.
2-Take without regard to meals.

Pregnancy level

C


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