Generic
Labetalol Hydrochloride
11 brands available in the market
At a glance
Labetalol Hydrochloride is used for the treatment of high blood pressure (hypertension) and heart-related chest pain (angina). It is also effective for treating high blood pressure in pregnancy. It slows the heart rate and relaxes blood vessels to improve heart efficiency.
Description
Labetalol Hydrochloride is an alpha and beta blocker that competitively inhibits adrenergic stimulation of beta-receptors in the myocardium, bronchial and vascular smooth muscle, and alpha1-receptors in vascular smooth muscle. It also has intrinsic beta2-agonist and membrane-stabilizing activity. The drug is completely absorbed from the GI tract with peak plasma levels in 1-2 hours. Plasma half-life is 6-8 hours. Approximately 55-60% of a dose is excreted in urine within 24 hours.
Indications
- Hypertension (high blood pressure)
- Hypertension in pregnancy
- Hypertensive crisis
- Angina (heart-related chest pain)
- Hypotensive anesthesia
- Hypertension after stroke
- Hypertension after myocardial infarction
Therapeutic class
Alpha and Beta-adrenergic Blocker
Pharmacological class
Alpha-1 + Non-selective Beta Blocker
Pharmacology
Labetalol is an adrenergic receptor-blocking agent that has both selective alpha-1 and nonselective beta-adrenergic receptor-blocking actions. Both alpha and beta-blocking actions contribute to a decrease in blood pressure in hypertensive patients.
Mechanism of action
Slows heart rate and relaxes blood vessels by blocking alpha-1 and beta receptors.
Dosage
Oral (Adult):
- Initial dose: 100 mg twice daily
- Maintenance dose: 200-400 mg twice daily
- Maximum dose: 2.4 g/day in 2-4 divided doses
- Elderly: Initial 50-100 mg twice daily; Maintenance 100-200 mg twice daily
Injection/Infusion:
- Hypertensive crisis: 20 mg slow IV (over 2 min), 40-80 mg every 10 min (max 300 mg)
- Hypertension in pregnancy: 20 mg/hr start, double every 30 min (max 160 mg/hr)
- Post-MI hypertension: 15 mg/hr start, gradually increase (max 120 mg/hr)
Administration
- Swallow tablet whole; do not chew, crush or break
- Take with food
- IV injection: Give slowly over at least 1 minute
- Infusion: Dilute with 5% Dextrose, 0.9% Sodium Chloride
- Patient should remain supine during and 3 hours after the procedure
Missed dose
If you miss a dose, take it as soon as you remember; skip if it's almost time for next dose.
Side effects
Common Side Effects:
- Dizziness
- Allergic reaction
- Ejaculation disorder
- Increased liver enzymes
- Difficulty in urination
Other Side Effects:
- Orthostatic hypotension (dizziness upon standing)
- Fatigue, weakness
- Headache
- Skin rash
- Nausea, vomiting
- Liver damage (rare)
Precautions & warnings
- Avoid driving or activities requiring concentration (may cause dizziness)
- Take with food
- Rise slowly when standing (to avoid orthostatic hypotension)
- Avoid alcohol (may worsen side effects)
- Do not stop suddenly (risk of heart attack and stroke)
- Discontinue if signs of liver injury occur
Contraindications
- 2nd and 3rd degree heart block
- Cardiogenic shock
- Obstructive airway disease (e.g., bronchial asthma)
- Uncompensated heart failure
- Severe bradycardia
- Sick sinus syndrome
- Prinzmetal's angina
- Severe peripheral arterial disease
Drug interactions
- Synergistic hypotensive effect with halothane
- Increased bioavailability with cimetidine
- Decreased bioavailability with glutethimide
- Additive hypotensive effect with nitroglycerin
- Increased tremor incidence with TCAs
- Increased risk of bradycardia and heart block with calcium channel blockers (verapamil, diltiazem)
Food interactions
Alcohol consumption is unsafe (may worsen side effects).
Use in pregnancy
Use in Pregnancy: Labetalol Hydrochloride may be unsafe during pregnancy. Animal studies have shown harmful effects on the fetus. However, it is used for hypertension in pregnancy. Consult your doctor.
Use in lactation
Use in Lactation: Labetalol Hydrochloride is probably safe during breastfeeding. Small amounts (~0.004% of maternal dose) are excreted in breast milk. Consult your doctor.
Pediatric use
Pediatric dose is established (hypertensive emergency: 0.4-1 mg/kg/hr IV).
Geriatric use
Elderly patients should start with reduced doses (50-100 mg twice daily).
Renal / hepatic impairment
Renal Impairment: Safe in patients with kidney disease; no dose adjustment needed. Regular blood pressure monitoring is recommended.
Hepatic Impairment: Use with caution in liver disease; dose adjustment may be needed.
Overdose effects
Overdose causes excessive hypotension and bradycardia. Treatment: Atropine (bradycardia), Digitalis and diuretics (heart failure), Norepinephrine (hypotension), Epinephrine (bronchospasm).
Storage conditions
Store in a cool and dry place protected from light; keep out of reach of children.
Chemical structure
Labetalol Hydrochloride