Details About Overdose or Poisoning Generic Salt :: Norepinephrine
Norepinephrine
Drug Pharmacology ::
I. Pharmacology. Norepinephrineis an endogenous catecholamine that stimulates mainly alpha-adrenergicreceptors. It is used primarily as a vasopressor to increase systemicvascular resistance and venous return to the heart. Norepinephrine isalso a weak beta-1-adrenergic receptor agonist, and it may increaseheart rate and cardiac contractility in patients with shock.Norepinephrine is not effective orally and is absorbed erraticallyafter subcutaneous injection. After intravenous administration, theonset of action is nearly immediate, and the duration of effect is 1–2minutes after the infusion is discontinued.
Drug Indications ::
Indications. Norepinephrineis used to increase blood pressure and cardiac output in patients withshock caused by venodilation, low systemic vascular resistance, orboth. Hypovolemia, depressed myocardial contractility, hypothermia, andelectrolyte imbalance should be corrected first or concurrently.
Drug Contra-Indications ::
III. Contraindications./b>
Uncorrected hypovolemia.
Norepinephrineis relatively contraindicated in patients with peripheral arterialocclusive vascular disease with thrombosis or ergot poisoning (seeErgot Derivatives).
Drug Adverse Effects ::
IV. Adverse effects
Severe hypertension, which may result in intracranial hemorrhage, pulmonary edema, or myocardial necrosis.
Aggravation of tissue ischemia, resulting in gangrene.
Tissue necrosis after extravasation.
Anxiety, restlessness, tremor, and headache.
E. Anaphylaxisinduced by sulfite preservatives in sensitive patients. Use withextreme caution in patients with known hypersensitivity to sulfitepreservatives.
F. Use with caution in patients intoxicated by chloral hydrate or halogenated or aromatic hydrocarbon solvents or anesthetics.
G. Use in pregnancy. This drug crosses the placenta and can cause placental ischemia and reduce uterine contractions.
Drug Lab Interactions ::
Drug or laboratory interactions
Enhancedpressor response may occur in the presence of cocaine and cyclicantidepressants owing to inhibition of neuronal reuptake.
Enhancedpressor response may occur in patients taking monoamine oxidaseinhibitors owing to inhibition of neuronal metabolic degradation.
Alpha- and beta-blocking agents may antagonize the adrenergic effects of norepinephrine.
Anticholinergicdrugs may block reflex bradycardia, which normally occurs in responseto norepinephrine-induced hypertension, enhancing the hypertensiveresponse.
E. Chloralhydrate overdose and cyclopropane and halogenated or aromatichydrocarbon solvents and anesthetics may enhance myocardial sensitivityto the arrhythmogenic effects of norepinephrine.
Drug Dose Management ::
Dosage and method of administration
Caution: Avoid extravasation.The intravenous infusion must be free flowing, and the infused veinshould be observed frequently for signs of infiltration (pallor,coldness, or induration).
1. Ifextravasation occurs, immediately infiltrate the affected area withphentolamine (see Phentolamine), 5–10 mg in 10–15 mL of normal saline(children, 0.1–0.2 mg/kg; maximum 10 mg) via a fine (25- to 27-gauge)hypodermic needle; improvement is evidenced by hyperemia and return tonormal temperature.
2. Alternatively, topical application of nitroglycerin paste and infiltration of terbutaline have been reported successful.
Intravenous infusion. Begin at 4–8 mcg/min (children, 1–2 mcg/min or 0.1 mcg/kg/min) and increase as needed every 5–10 minutes.
Drug Chemical Formulations ::
Formulations. Norepinephrinebitartrate is oxidized rapidly on exposure to air; it must be kept inits airtight ampule until immediately before use. If the solutionappears brown or contains a precipitate, do not use it. The stocksolution must be diluted in 5% dextrose or 5% dextrose-saline forinfusion; usually, a 4-mg ampule is added to 1 L of fluid to provide 4mcg/mL of solution.
Parenteral. Norepinephrine bitartrate (Levophed), 1 mg/mL, 4-mL ampule. Contains sodium bisulfite as a preservative.
The suggested minimum stocking level to treat a 70-kg adult for the first 24 hours is five ampules.
