Noradrenaline

Norepinephrine

Mechanism :

Norepinephrine is a sympathomimetic amine which differs from epinephrine by the absence of a methyl group on the nitrogen atom. Norepinephrine functions as a peripheral vasoconstrictor (alpha-adrenergic action) and as an inotropic stimulator of the heart and dilator of coronary arteries (beta-adrenergic action).

Indication :

• Cardiac surgery - post-op low cardiac output
• Acute hypotension
• Shock
• Cardiac arrest

Contraindications :

Norepinephrine should not be given to patients who are hypotensive from blood volume deficits except as an emergency measure. If norepinephrine is continuously administered to maintain blood pressure in the absence of blood volume replacement, the following may occur: severe peripheral and visceral vasoconstriction, decreased renal perfusion and urine output, poor systemic blood flow, tissue hypoxia, and lactate acidosis.

Norepinephrine should also not be given to patients with mesenteric or peripheral vascular thrombosis unless it is necessary as a life-saving procedure.

Cyclopropane and halothane anesthetics increase cardiac autonomic irritability, hence the use of Norepinephrine during cyclopropane and halothane anesthesia is generally considered contraindicated.

Dosing :

IV infusion 0.05-0.1 mcg/kg/min (Max: 1-2 mcg/kg/min). Monitor ECG and hemodynamic parameters.

Adverse Effect :

Ischemic injury due to potent vasoconstrictor action and tissue hypoxia, bradycardia, probably as a reflex result of a rise in blood pressure, arrhythmias, anxiety, transient headache, confusion, headache, restlessness, nausea, vomiting, respiratory difficulty, extravasation necrosis at injection site, sweating, tremors, urinary retention.

Interaction :

Cyclopropane and Halothane Anesthetics: Increase cardiac automatic irritability and sensitize the myocardium to the action of intravenously administered epinephrine or norepinephrine, hence, the risk of producing ventricular tachycardia or fibrillation.
Monoamine Oxidase Inhibitors: Norepinephrine should be used with extreme caution in patients receiving (MAOI) or antidepressants of the triptyline or imipramine types, because severe, prolonged hypertension may result.

Renal Dose :

Hepatic Dose :