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Indications and Dosage
Intravenous
Acute hypotensive states Adult: As norepinephrine base: Initially, 0.4-0.8 mg/hour given via infusion. Then titrate dose in steps of 0.05-0.1 mcg/kg/min to maintain normotension or achieve an adequate mean arterial blood pressure depending on patient's condition.
Elderly: Initial dose should be at low end of dose range. |
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Reconstitution
Intravenous:
Dilute with 5% glucose inj, with or without sodium chloride; dilution with sodium chloride inj alone is not recommended. |
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Incompatibility
Intravenous:
Incompatible with alkali and oxidising agents, barbiturates, chlorphenamine, chlorothiazide, nitrofurantoin, novobiocin, phenytoin, sodium bicarbonate, sodium iodide, streptomycin, insulin. |
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Contraindications
Hypertension. Pregnancy. Patients with peripheral or mesenteric vascular thrombosis unless necessary as a life-saving procedure.
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Special Precautions
Not a substitute for replacement of blood, plasma, fluids, and/or electrolytes; correct volume depletion prior to admin. Identify and correct hypoxia, hypercapnia and acidosis prior to or during admin. Avoid extravasation as tissue necrosis may occur. Avoid inj into leg veins, especially in elderly or those with occlusive vascular diseases, arteriosclerosis, DM or Buerger's disease. Hypertensive or hyperthyroid patients. In conjunction with local anaesthetics, do not use in fingers, toes, ears, nose or genitalia. Lactation.
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Adverse Reactions
Hypertension, headache, peripheral ischaemia, bradycardia, arrhythmias, anxiety, skin necrosis (with extravasation), dyspnoea, respiratory difficulty.
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IM/IV/Parenteral: C
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Overdosage
Symptoms: Hypertension, sweating, cerebral haemorrhage, convulsions.
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Drug Interactions
Guanethidine, methyldopa, reserpine, TCAs may increase pressor response to norepinephrine.
Potentially Fatal: Increased risk of arrhythmias with cocaine, cyclopropane or halogenated hydrocarbon anaesthetics. Hypertensive crisis may occur with MAOIs. Hypertensive effects may be increased by nonselective β-blockers. |
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Action
Description: Norepinephrine is a direct-acting sympathomimetic which stimulates β1- and α-adrenergic receptors. Its α-agonist effects cause vasoconstriction, thereby raising systolic and diastolic BP with reflex slowing of heart rate.
Onset: Rapid. Duration: Short; stops within 1-2 min after discontinuing the infusion. Pharmacokinetics: Absorption: Oral: Destroyed in the GI tract; SC: Poorly absorbed. Distribution: Mainly localises in sympathetic nervous tissue; crosses the placenta but not the blood-brain barrier. Metabolism: Metabolised in the liver and in other tissues by the enzymes catechol-O-methyltransferase (COMT) and monoamine oxidase (MAO). Excretion: Via urine (mainly as metabolites). |
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Storage
Intravenous:
Store at room temperature (25°C) and protect from light. Store in tight, light-resistant containers as norepinephrine is readily oxidised. Do not use if discoloured (e.g. pink, dark yellow, brown) or if there is a precipitate. |
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MIMS Class
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