Generic Medicine Info
Indications and Dosage
Hypertension after myocardial infarction
Adult: Initiate infusion at a rate of 15 mg/hour, then gradually increased up to a Max of 120 mg/hour depending on blood pressure control.
Elderly: Lower initial doses may be required.

Emergency treatment of hypertension
Adult: Dosage must be individualised based on severity and patient response. As inj: 50 mg via bolus inj over at least 1 minute; if necessary, may be repeated at 5-minute intervals until a satisfactory response occurs. Max total dose: 200 mg. Alternatively, an initial dose of up to 20 mg via slow inj over 2 minutes; subsequent doses of 40 mg or 80 mg may be given at 10-minute intervals until a desired supine blood pressure is achieved or a total of 300 mg has been injected. As an infusion: Initiate infusion at a rate of 2 mg/minute until a satisfactory response occurs, then stop the infusion. Usual effective dose: 50-200 mg, but larger doses may be given as necessary. Adjust dosage and rate of infusion according to the blood pressure response. Patient should remain supine during and for up to 3 hours after administration. Dosage recommendations may vary among countries or individual products. Refer to specific product guidelines.
Elderly: Lower initial doses may be required.

Hypertension in pregnancy
Adult: Initiate infusion at a rate of 20 mg/hour; dose may be doubled every 30 minutes until a satisfactory reduction in blood pressure has been obtained or a dose of 160 mg/hour is reached. Higher doses may be necessary in some cases.

Hypotensive anaesthesia
Adult: Initially, 10-20 mg depending on the patient’s age and condition. If satisfactory hypotension is not achieved after 5 minutes, increments of 5-10 mg must be given until the desired level of blood pressure is attained. In patients for whom halothane is contraindicated, a higher initial dose (25-30 mg) may be required.
Elderly: Lower initial doses may be required.

Hypertension in pregnancy
Adult: Initially, 100 mg bid; if necessary, may be increased in increments of 100 mg bid at weekly intervals. Further dose titration to a 3 times daily regimen may be required based on the severity of hypertension. Max: 2,400 mg daily.

Adult: Initially, 100 mg bid; if necessary, may be gradually increased in increments of 100 mg bid at intervals of 14 days according to response. Maintenance: 200-400 mg bid. For severe, refractory hypertension: Doses of up to 2,400 mg daily in 3-4 divided doses may be given.
Elderly: Initially, 50-100 mg bid. Maintenance: 100-200 mg bid.
Renal Impairment
Dosage reduction may be needed.
Hepatic Impairment
Dosage reduction may be needed.
Should be taken with food. Take immediately after meals.
IV infusion: Dilute the amp contents (200 mg) with 200 mL of compatible IV fluids (e.g. 0.9% NaCl inj, 5% dextrose inj, Ringer's inj, Lactated Ringer's inj) to make a 1 mg/mL solution.
IV: May form a precipitate with Na bicarbonate 4.2% inj, alkaline agents (e.g. furosemide), ceftriaxone, and heparin.
Cardiogenic shock, sick sinus syndrome (including sino-atrial block), 2nd- or 3rd-degree heart block, Prinzmetal's angina, severe bradycardia (<45-50 bpm), uncompensated heart failure, overt heart failure; uncontrolled, incipient or digitalis-refractory heart failure; current or history of bronchospasm and bronchial asthma, history of obstructive airway disease, untreated phaeochromocytoma, metabolic acidosis, severe peripheral circulatory disturbances, hypotension, other conditions associated with severe and prolonged hypotension. Labetalol IV infusion should not be used to control hypertensive episodes after myocardial infarction when peripheral vasoconstriction suggests low cardiac output.
Special Precautions
Patient with 1st-degree heart block, compensated heart failure, poor cardiac reserve, peripheral circulatory disorders (Raynaud's disease, intermittent claudication), phaeochromocytoma, diabetes mellitus, thyroid disease, history of psoriasis, myasthenia gravis, history of severe anaphylaxis to allergens. Patients requiring anaesthesia, or those undergoing surgery (including cataract surgery). May mask signs of hyperthyroidism (e.g. tachycardia) and acute hypoglycaemia. Avoid abrupt withdrawal, particularly in patients with ischaemic heart disease. Hepatic or renal impairment. Elderly. Pregnancy and lactation.
Adverse Reactions
Significant: Bradycardia, CHF, symptomatic hypotension (with or without syncope), postural hypotension, bronchospasm; exacerbation of angina, ventricular arrhythmia and MI (following abrupt withdrawal); may precipitate or aggravate symptoms of arterial insufficiency (in patients with peripheral circulatory disorders or Raynaud's disease); induction or exacerbation of psoriasis, dry eyes, anaphylactic reactions.
Cardiac disorders: Rarely, heart block.
Ear and labyrinth disorders: Vertigo.
Eye disorders: Impaired vision.
Gastrointestinal disorders: Nausea, vomiting, diarrhoea, epigastric pain, dyspepsia, dysgeusia.
General disorders and administration site conditions: Fatigue, asthenia, drug fever, lethargy.
Hepatobiliary disorders: Jaundice, hepatitis.
Investigations: Increased serum creatinine, BUN, and LFTs; positive antinuclear antibodies unassociated with disease.
Musculoskeletal and connective tissue disorders: Cramps, toxic myopathy.
Nervous system disorders: Headache, dizziness, drowsiness, tremor, paraesthesia.
Psychiatric disorders: Confusion, sleep disturbance, nightmares, depressed mood.
Renal and urinary disorders: Urinary retention, difficulty in micturition.
Reproductive system and breast disorders: Ejaculatory failure, impotence, nipple pain.
Respiratory, thoracic and mediastinal disorders: Nasal congestion, dyspnoea.
Skin and subcutaneous tissue disorders: Hyperhidrosis, rash, tingling sensation in the scalp, reversible lichenoid rash, SLE, reversible alopecia.
Vascular disorders: Peripheral coldness.
Potentially Fatal: Rarely, severe hepatocellular injury (reversible).
IV/Parenteral/PO: C
Patient Counseling Information
This drug may cause dizziness or fatigue, if affected, do not drive or operate machinery.
Monitoring Parameters
Monitor blood pressure and heart rate before and after the 1st dose and during dose changes; hepatic function periodically; glucose levels in patients with diabetes mellitus. Perform close pulse, cardiac, and blood pressure monitoring during and after completion of IV inj or infusion.
Symptoms: Bradycardia, hypotension, bronchospasm and acute cardiac insufficiency. Management: Performing gastric lavage or administration of activated charcoal and a laxative may be considered to prevent further absorption shortly after ingestion. Artificial respiration may be required. Administer atropine or methylatropine in case of bradycardia or extensive vagal reactions. Hypotension and shock may be treated with plasma or plasma substitutes and catecholamines, if necessary. May counteract the β-blocking effect by slow IV administration of approx 5 mcg/min (starting dose) isoprenaline hydrochloride or approx 2.5 mcg/min (starting dose) dobutamine until the required effect has been obtained; IV administration of 8-10 mg glucagon may be considered if the desired effect is not achieved. May consider giving Ca ions or using a cardiac pacemaker if necessary.
Drug Interactions
Enhanced hypotensive effects with ACE inhibitors, angiotensin-II antagonists, aldesleukin, alprostadil, anxiolytics, hypnotics, diuretics, α-blockers, TCAs, phenothiazines, and barbiturates. May cause the attenuation of reflex tachycardia and increased risk of hypotension with anaesthetics. May enhance the hypotensive effects of halothane. NSAIDs, corticosteroids, estrogens and progesterones may antagonise the hypotensive effects of labetalol. May result in bradycardia and hypertension when given with epinephrine. Labetalol may blunt the reflex tachycardia produced by glyceryl trinitrate. May enhance the blood glucose-lowering effects of insulin and oral antidiabetic agents. May increase the risk of hypotension with dihydropyridine Ca antagonists (e.g. nifedipine). May cause hypotension, bradycardia and asystole with verapamil and diltiazem. May increase the atrioventricular conduction time with digitalis glycosides. May increase the rebound hypertensive effect of clonidine (when abruptly withdrawn). Class I antiarrhythmic agents (e.g. disopyramide, quinidine) and amiodarone may potentiate the effects on atrial conduction time and induce negative inotropic effect. Bioavailability may be increased with cimetidine and hydralazine. May increase the incidence of tremors with TCAs. May increase the risk of bradycardia with antimalarials (e.g. quinine, mefloquine). Labetalol may increase the vasoconstricting effects of ergot derivatives.
Food Interaction
Bioavailability may be increased with food and alcohol.
Lab Interference
May result in false-positive aldosterone/renin ratio. May cause false-positive urine catecholamines, metanephrine, normetanephrine, and vanillylmandelic acid (VMA) when measured by fluorometric or photometric methods. May lead to false-positive test for amphetamine urine screening if measured by thin-layer chromatography or radioenzymatic assay. May interfere with the result of metaiodobenzylguanidine (MIBG) scintigraphy.
Mechanism of Action: Labetalol exhibits both a nonselective β-adrenergic and selective α1-adrenergic blocking properties. It lowers blood pressure by blocking peripheral arteriolar α-adrenoceptors, thereby reducing peripheral resistance. It also concurrently inhibits β-adrenoceptors in the heart from the reflex sympathetic drive that may occur. Labetalol does not significantly reduce cardiac output at rest or after moderate exercise.
Onset: 20 minutes to 2 hours (oral); within 5 minutes (IV).
Duration: Dose dependent: 8-12 hours (oral); 16-18 hours (IV).
Absorption: Readily and completely absorbed from the gastrointestinal tract. Bioavailability may be increased with food. Time to peak plasma concentration: 1-2 hours (oral).
Distribution: Rapidly and widely distributed into the extravascular space. Crosses the placenta and enters breast milk. Apparent volume of distribution: 2.5-15.7 L/kg. Plasma protein binding: Approx 50%.
Metabolism: Metabolised in the liver mainly via glucuronide conjugation to inactive metabolites; undergoes extensive first-pass metabolism.
Excretion: Via urine (approx 55-60% as glucuronide conjugates and 5% as unchanged drug); faeces (12-27% as metabolites). Elimination half-life: Approx 6-8 hours (oral); approx 5.5 hours (IV).
Chemical Structure

Chemical Structure Image

Source: National Center for Biotechnology Information. PubChem Compound Summary for CID 3869, Labetalol. Accessed Sept. 27, 2022.

Tab: Store below 30°C. Protect from light and moisture. Solution for inj or infusion: Store between 15-30°C. Do not freeze. Protect from light.
MIMS Class
ATC Classification
C07AG01 - labetalol ; Belongs to the class of alpha and beta blocking agents. Used in the treatment of cardiovascular diseases.
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Labetalol Hydrochloride Tablet, Film Coated (Marlex Pharmaceuticals Inc). DailyMed. Source: U.S. National Library of Medicine. Accessed 11/08/2022.

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Trandate 100 mg Film-coated Tablets (RPH Pharmaceuticals AB). MHRA. Accessed 11/08/2022.

Trandate 5 mg/mL Solution for Injection (RPH Pharmaceuticals AB). MHRA. Accessed 11/08/2022.

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Disclaimer: This information is independently developed by MIMS based on Labetalol from various references and is provided for your reference only. Therapeutic uses, prescribing information and product availability may vary between countries. Please refer to MIMS Product Monographs for specific and locally approved prescribing information. Although great effort has been made to ensure content accuracy, MIMS shall not be held responsible or liable for any claims or damages arising from the use or misuse of the information contained herein, its contents or omissions, or otherwise. Copyright © 2024 MIMS. All rights reserved. Powered by
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