Labetalol

Provider Level

RN/Paramedic

Class

Alpha and beta adrenergic antagonist

Mechanism of Action

Non-selective beta-adrenergic and selective alpha-1-adrenergic receptor antagonist. Lowers blood pressure by decreasing systemic vascular resistance without significant reflex tachycardia.

Indications

Hypertensive emergencies, severe hypertension.

Contraindications

Bronchial asthma, overt cardiac failure, greater than first-degree heart block, cardiogenic shock, severe bradycardia, conditions associated with severe and prolonged hypotension.

Routes

IV, IO

Onset / Duration

Onset is 2 to 5 minutes. Duration is 2 to 4 hours.

Adverse Effects

Symptomatic postural hypotension, bradycardia, dizziness, fatigue, ventricular arrhythmias, bronchospasm, nausea, vomiting.

Precautions & Interactions

Continuous blood pressure and ECG monitoring required. Use with extreme caution in patients with reactive airway disease or compensated heart failure. Concurrent use with calcium channel blockers may cause severe hypotension and bradycardia.

Special Considerations

Authorized provider levels: RN/Paramedic. Do not use in patients with cocaine-induced acute coronary syndrome due to the risk of unopposed alpha-adrenergic stimulation. Patient should remain supine during and immediately after administration to prevent orthostatic hypotension.