Name

labetalol (Normodyne®, Trandate®)

Class

Alpha and beta adrenergic antagonist

Description/Mechanism

Labetalol is a competitive alpha 1 receptor blocker as well as a nonselective beta receptor blocker. Alpha 1 antagonism causes vasodilation and a decrease in peripheral resistance. Beta blockade prevents reflex tachycardia. Combined, there is little decrease in cardiac output.

Onset

Within 5 minutes

Duration

3-6 hours

Indications

Hypertension

Excessive sympathetic stimulation, ie cocaine and amphetamine toxicity.

Contraindications

Bronchial asthma

Congestive Heart Failure

Second and third degree heart block

Bradycardia

Cardiogenic shock

Adverse Reactions

Headache

Dizziness

Ventricular dysrhythmias

Hypotension

Dyspnea

Allergic reaction

Facial flushing

Diaphoresis

Postural hypotension

Drug Interactions

Bronchodilator effects of beta adrenergic agonists may be blunted by labetalol

Nitroglycerin may augment hypotensive effects.

Supplied

100 mg in 20 ml of solvent ampule (5mg/ml)

Dose/Administration

Adult

IV: 5-20 mg slow over 2 min, repeat at 10-40 mg every 10 minutes. Max: 300 mg.

Infusion: infuse at a rate of 2mg/min, titrate to supine blood pressure. Typical preparation: mix 200 mg in 250 ml D5W for a concentration of (0.8mg/ml).

Pediatric

Not recommended

Special Consideration

Pregnancy Safety: Category C

Blood pressure, pulse rate, ECG should be continuously monitored.

Observe for signs of CHF, bradycardia, bronchospasm

Latetalol should only be administered with the patient in a supine position.