Norfine

Emergency restoration of BP in acute hypotensive states eg, shock.

Adult Initially 10-20 mL/hr (0.16-0.32 mL/min), equiv to 0.8-1.6 mg/hr (0.4-0.8 mg/hr). Titrate dose according to pressor effect observed.

Hypersensitivity. Hypotension due to blood vol deficit (hypovolaemia). Patients receiving cyclopropane or halothane anaesth or any other cardiac sensitising agent or who exhibit profound hypoxia or hypercarbia.

Do not use undiluted. Should not be given to patients who are hypotensive from blood vol deficits except as an emergency measure to maintain coronary & cerebral artery perfusion until blood vol replacement therapy can be completed. Where indicated, institute & maintain appropriate replacement therapy of blood or fluid together w/ adoption of the supine position w/ elevation of the legs prior to &/or during therapy. Frequently check BP & rate of flow during infusion. Prolonged administration may result in plasma vol depletion which should be continuously corrected by appropriate water & electrolyte replacement therapy. Caution in patients w/ major left ventricular dysfunction associated w/ acute hypotension; coronary, mesenteric or peripheral vascular thrombosis; hypotension following MI & those w/ angina, particularly Prinzmetal's variant angina, diabetes, HTN or hyperthyroidism; liver failure, severe renal dysfunction, ischemic heart diseases & elevated ICP. Reduce dose if heart rhythm disorders occur during treatment. Overdoses or conventional doses in hypersensitive persons (eg, hyperthyroid patients) may cause severe HTN w/ violent headache, photophobia, stabbing retrosternal pain, pallor, intense sweating & vomiting. Increases level of blood glucose (caution in diabetics). Cardiac arrhythmias may arise w/ cardiac sensitizing agents, & may be more likely in patients w/ hypoxia or hypercarbia. Gradually reduce infusions when w/drawing therapy. Care should be taken to avoid extravasation into the tissues; stop infusion & infiltrate area w/ saline soln containing phentolamine if extravasation occurs. No experience in treatment of hepatically or renally impaired patients. Weigh possible risks to the foetus against the potential benefit to the mother. Caution when administering to a nursing woman. Not recommended in childn. Elderly may be especially sensitive to effects due to greater frequency of hepatic, renal or cardiac dysfunction & concomitant disease or other drug therapy.

Anxiety, insomnia, confusion, weakness, psychotic state; transient headache, tremor; bradycardia, arrhythmia, ECG change, tachycardia, cardiogenic shock, stress cardiomyopathy, palpitations, increase in the contractility of the cardiac muscle resulting from β-adrenergic effect on the heart (inotrope & chronotrope); HTN, peripheral ischaemia including gangrene of the extremities, plasma vol depletion w/ prolonged use, ischaemic injury due to potent vasoconstrictor action may result in coldness & paleness of the limbs; nausea, vomiting; paleness, scarification of the skin, bluish skin colour, hot flushes or skin redness, skin rash, hives or itching; urine retention; dyspnoea; extravasation, inj site necrosis.

Inadvisable combinations: Severe ventricular arrhythmia w/ volatile halogenated anaesth. Paroxysmal HTN w/ the possibility of arrhythmia w/ imipramine antidepressants; serotoninergic-adrenergic antidepressants. Concomitant use w/ digitalis glycosides; levodopa. Significantly increased toxicity w/ chlorpheniramine HCl, tripelennamine HCl & desipramine. Antihistamines may block intake of catecholamines by peripheral tissues & increase toxicity of norepinephrine. May cause serious cardiac arrhythmias w/ cyclopropane, halothane, chloroform, enflurane or other halogenated anaesth. Combinations requiring precautions for use: Increased in the pressor action w/ non-selective MAOIs. Risk of increase in the pressor action w/ selective MAO-A inhibitors; linezolid. Effects may be enhanced by guanethidine, guanadrel, reserpine, methyldopa or TCAs, amphetamine, doxapram, mazindol, rauwolfia alkaloids. Severe HTN may result w/ α- & β-blockers. May cause increased cardiac effects w/ thyroid hormones, cardiac glycosides, antiarrhythmic. Vasopressor & vasoconstrictive effects may be enhanced w/ ergot alkaloids (ergoloid mesylates, ergotamine, dihydroergotamine, ergometrine, methylergometrine, & methysergide) or oxytocin. Concomitant administration of propofol may lead to propofol infusion syndrome. Diminished antidiuretic effect w/ desmopressin or vasopressin. Decreased effect w/ lithium.

Vasoconstrictors

C01CA03 - norepinephrine ; Belongs to the class of adrenergic and dopaminergic cardiac stimulants excluding glycosides. Used in the treatment of hypotension.

Rx