General: Avoid Hypertension: Because of the potency of N-EPI and because of varying response to pressor substances, the possibility always exists that dangerously high blood pressure may be produced with overdoses of this pressor agent. It is desirable, therefore, to record blood pressure every two minutes from the time administration is started until the desired blood pressure is obtained, then every five minutes if the administration is to be continued.
The rate of flow must be watched constantly, and the patient should never be left unattended while receiving N-EPI. Headache may be a symptom of hypertension due to overdosage.
Site of Infusion: Whenever possible, infusions of N-EPI should be given into a large vein, particularly an antecubital vein because, when administered into this vein, the risk of necrosis of the overlying skin from prolonged vasoconstriction is apparently very slight. Some authors have indicated that the femoral vein is also an acceptable route of administration. A catheter tie-in technique should be avoided, if possible, since the obstruction to blood flow around the tubing may cause stasis and increased local concentration of the drug. Occlusive vascular diseases (for example, atherosclerosis, arteriosclerosis, diabetic endarteritis, Buerger's disease) are more likely to occur in the lower than in the upper extremity.
Therefore, one should avoid the veins of the leg in elderly patients or in those suffering from such disorders. Gangrene has been reported in a lower extremity when infusions of N-EPI were given in an ankle vein.
Extravasation: The infusion site should be checked frequently for free flow. Care should be taken to avoid extravasation of N-EPI into the tissues, as local necrosis might ensue due to the vasoconstrictive action of norepinephrine. Blanching along the course of the infused vein, sometimes without obvious extravasation, has been attributed to vasa vasorum constriction with increased permeability of the vein wall, permitting some leakage.
This also may progress on rare occasions to superficial slough, particularly during infusion into leg veins in elderly patients or in those suffering from obliterative vascular disease. Hence, if blanching occurs, consideration should be given to the advisability of changing the infusion site at intervals to allow the effects of local vasoconstriction to subside.
IMPORTANT: Antidote for Extravasation Ischemia: To prevent sloughing and necrosis in areas in which extravasation has taken place, the area should be infiltrated as soon as possible with 10 mL to 15 mL of saline solution containing 5 mg to 10 mg of Regitine (brand of phentolamine), an adrenergic blocking agent. A syringe with a fine hypodermic needle should be used, with the solution being infiltrated liberally throughout the area, which is easily identified by its cold, hard and pallid appearance. Sympathetic blockade with phentolamine causes immediate and conspicuous local hyperemic changes if the area is infiltrated within 12 hours. Therefore, phentolamine should be given as soon as possible after the extravasation is noted.
Carcinogenesis, Mutagenesis, Impairment of Fertility: Studies have not been performed.
Use in Children: Safety and effectiveness in paediatric patients have not been established.
Use in Elderly: Reported clinical experience has not identified differences in responses between the elderly and younger patients. In general, dose selection for an elderly patient should be cautious, usually starting at the low end of the dosing range, reflecting the greater frequency of decreased hepatic, renal, or cardiac function, and of concomitant disease or other drug therapy.
N-EPI should not be administered into the veins in the leg in elderly patients.
Effects on Ability to Drive and Use Machine: None stated.