Brand Names

LABETALOL HYDROCHLORIDE
LABETALOL HYDROCHLORIDE IN DEXTROSE
LABETALOL HYDROCHLORIDE IN SODIUM CHLORIDE
NORMODYNE
NORMOZIDE
TRANDATE
TRANDATE HCT

Indications and Usage

Labetalol HCl tablets are indicated in the management of hypertension. Labetalol HCl tablets may be used alone or in combination with other antihypertensive agents, especially thiazide and loop diuretics.

Dosage and Administration

DOSAGE MUST BE INDIVIDUALIZED. The recommended initialdosage is 100 mg twicedaily 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. every 2 or 3 days. The usual maintenancedosage of labetalol HCl is between 200 mg and 400 mg twicedaily. Since the full antihypertensive effect of labetalol HCl is usually seen within the first 1 to 3 hours of the initial dose or dose increment, the assurance of a lack of an exaggerated hypotensive response can be clinically established in the office setting. The antihypertensive effects of continued dosing can be measured at subsequent visits, approximately 12 hours after a dose, to determine whether further titration is necessary. Patients with severe hypertension may require from 1,200 mg to 2,400 mg per day, with or without thiazide diuretics. Should side effects (principally nausea or dizziness) occur with these doses administered twice daily, the same total daily dose administered three times daily may improve tolerability and facilitate further titration. Titration increments should not exceed 200 mg twice daily. When a diuretic is added, an additive antihypertensive effect can be expected. In some cases this may necessitate a labetalol HCl dosage adjustment. As with most antihypertensive drugs, optimal dosages of labetalol HCl tablets are usually lower in patients also receiving a diuretic. When transferring patients from other antihypertensive drugs, labetalol HCl tablets should be introduced as recommended and the dosage of the existing therapy progressively decreased. Elderly Patients As in the general patient population, labetalol therapy may be initiated at 100 mg twice daily and titrated upwards in increments of 100 mg twice daily as required for control of blood pressure. Since some elderly patients eliminate labetalol more slowly, however, adequate control of blood pressure may be achieved at a lower m

Contraindications

Labetalol HCl tablets are 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.

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 HCl tablets 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. The incidence rates of adverse reactions listed in the following table were derived from multicenter controlled clinical trials comparing labetalol HCl, placebo, metoprolol, and propranolol over treatment periods of 3 and 4 months. Where the frequency of adverse effects for labetalol HCl and placebo is similar, causal relationship is uncertain. The rates are based on adverse reactions considered probably drug related by the investigator. If all reports are considered, the rates are somewhat higher (e.g., dizziness 20%, nausea 14%, fatigue 11%), but the overall conclusions are unchanged. Labetalol HCl (n=227) % Placebo (n=98) % Propranolol (n=84) % Metoprolol (n=49) % Body as a Whole Fatigue 5 0 12 12 Asthenia 1 1 1 0 Headache 2 1 0 2 Gastrointestinal Nausea 6 1 1 2 Vomiting <1 0 0 0 Dyspepsia 3 1 1 0 Abdominal pain 0 0 1 2 Diaarrhea <1 0 2 0 Taste distortion 1 0 0 0 Central and Peripheral Nervous Systems Dizziness 11 3 4 4 Paresthesias <1 0 0 0 Drowsiness <1 2 2 2 Autonomic Nervous System Nasal stuffiness 3 0 0 0 Ejaculation failure 2 0 0 0 Impotence 1 0 1 3 Increased sweating <1 0 0 0 Cardiovascular Edema 1 0 0 0 Postural hypotension 1 0 0 0 Bradycardia 0 0 5 12 Respiratory Dyspnea 2 0 1 2 Skin Rash 1 0 0 0 Special Senses Vision abnormality 1 0 0 0 Vertigo 2 1 0 0 The adverse effects were reported spontaneously and are representative of the incidence of adverse effects that may be observed in a properly selected hypertensive patient population, i.e. a group excluding patients with bronchosp

Drug Interactions

In one survey, 2.3% of patients taking labetalol HCl in combination with tricyclic antidepressants experienced tremor as compared to 0.7% reported to occur with labetalol HCl alone. The contribution of each of the treatments to this adverse reaction is unknown but the possibility of a drug interaction cannot be excluded. Drugs possessing beta-blocking properties can blunt the bronchodilator effect of beta-receptor agonist drugs in patients with bronchospasm; therefore, doses greater than the normal antiasthmatic dose of beta-agonist bronchodilator drugs may be required. Cimetidine has been shown to increase the bioavailability of labetalol HCl. Since this could be explained either by enhanced absorption or by an alteration of hepatic metabolism of labetalol HCl, special care should be used in establishing the dose required for blood pressure control in such patients. Synergism has been shown between halothane anesthesia and intravenously administered labetalol HCl. During controlled hypotensive anesthesia using labetalol HCl in association with halothane, high concentrations (3% or above) of halothane should not be used because the degree of hypotension will be increased and because of the possibility of a large reduction in cardiac output and an increase in central venous pressure. The anesthesiologist should be informed when a patient is receiving labetalol HCl. Labetalol HCl blunts the reflex tachycardia produced by nitroglycerin without preventing its hypotensive effect. If labetalol HCl is used with nitroglycerin in patients with angina pectoris, additional antihypertensive effects may occur. Care should be taken if labetalol is used concomitantly with calcium antagonists of the verapamil type. Both digitalis glycosides and beta-blockers slow atrioventricular conduction and decrease heart rate. Concomitant use can increase the risk of bradycardia. Risk of Anaphylactic Reaction While taking beta-blockers, patients with a history of severe anaphylactic reaction t

Overdosage

Overdosage with labetalol HCl causes excessive hypotension that is posture sensitive and, sometimes, excessive bradycardia. Patients should be placed supine and their legs raised if necessary to improve the blood supply to the brain. If overdosage with labetalol HCl follows oral ingestion, gastric lavage or pharmacologically induced emesis (using syrup of ipecac) may be useful for removal of the drug shortly after ingestion. The following additional measures should be employed if necessary: Excessive bradycardia- administer atropine or epinephrine. Cardiac failure- administer a digitalis glycoside and a diuretic. Dopamine or dobutamine may also be useful. Hypotension- administer vasopressors, e.g., norepinephrine. There is pharmacological evidence that norepinephrine may be the drug of choice. Bronchospasm- administer epinephrine and/or an aerosolized beta 2-agonist. Seizures- administer diazepam. In severe beta-blocker overdose resulting in hypotension and/or bradycardia, glucagon has been shown to be effective when administered in large doses (5 mg to 10 mg rapidly over 30 seconds, followed by continuous infusion of 5 mg per hour that can be reduced as the patient improves). Neither hemodialysis nor peritoneal dialysis removes a significant amount of labetalol HCl from the general circulation (<1%). The oral LD 50value of labetalol HCl in the mouse is approximately 600 mg/kg and in the rat is >2g/kg. The intravenous LD 50in these species is 50 mg/kg to 60 mg/kg.

⚠ Caution

Medical Disclaimer: This information is for educational purposes only. Always consult a healthcare professional before taking any medication.