Ingredients in every 4 ml
Each package contains
|ATC Level 1||C - Cardiovascular system|
|ATC Level 2||C01 - Cardiac Therapy Drugs|
|ATC Level 3||C01C - Cardiac Stimulants excl. Cardiac Glycosides|
Add 4 ml (4 mg) from norepinephrine’s ampoules to 1,000 ml of a 5% dextrose containing solution. Each ml of this dilution contains 4 micrograms of the base of norepinephrine. Give this solution by intravenous infusion. Insert a plastic intravenous catheter through a suitable bore needle well advanced centrally into the vein and securely fixed with adhesive tape, avoiding, if possible, a catheter tie-in technique as this promotes stasis. An I.V. drip chamber or other suitable metering device is essential to permit an accurate estimation of the rate of flow in drops per minute. After observing the response to an initial dose of 2 ml to 3 ml (from 8-12 mcg of base) per minute, adjust the rate of flow to establish and maintain a low normal blood pressure (usually 80 mmHg to 100 mmHg systolic) sufficient to maintain the circulation to vital organs. In previously hypertensive patients, it is recommended that the blood pressure should be raised no higher than 40 mmHg below the pre-existing systolic pressure. The average maintenance dose ranges is from 0.5-1 ml per minute (from 2 mcg to 4 mcg of base).
Great individual variation occurs in the dose required to attain and maintain an adequate blood pressure. In all cases, dosage of norepinephrine should be titrated according to the response of the patient. Occasionally much larger or even enormous daily doses (as high as 68 mg base or 17 ampoules) may be necessary if the patient remains hypotensive, but occult blood volume depletion should always be suspected and corrected when present. Central venous pressure monitoring is usually helpful in detecting and treating this situation.
The degree of dilution depends on clinical fluid volume requirements. If large volumes of fluid (dextrose) are needed at a flow rate that would involve an excessive dose of the pressor agent per unit of time, a solution more dilute than 4 mcg per ml should be used. On the other hand, when large volumes of fluid are clinically undesirable, a concentration greater than 4 mcg per ml may be necessary.
Duration of therapy
The infusion should be continued until adequate blood pressure and tissue perfusion are maintained without therapy. Infusions of norepinephrine should be reduced gradually, avoiding abrupt withdrawal. In some of the reported cases of vascular collapse due to acute myocardial infarction, treatment was required for up to six days.
ADJUNCTIVE TREATMENT IN CARDIAC ARREST
Infusions of norepinephrine are usually administered intravenously during cardiac resuscitation to restore and maintain an adequate blood pressure after an effective heartbeat and ventilation have been established by other means. (Norepinephrine's β-adrenergic stimulating action is also thought to increase the strength and effectiveness of systolic contractions once they occur).
To maintain systemic blood pressure during the management of cardiac arrest, norepinephrine is used in the same manner as described under “restoration of blood pressure in acute hypotensive states”.
For the restoration of blood pressure in certain acute hypotensive states (e.g. pheochromocytomectomy, sympathectomy, poliomyelitis, spinal anesthesia, myocardial infarction, septicemia, blood transfusion, and drug reactions). As an adjunct in the treatment of cardiac arrest and severe hypotension. To restore and maintain an adequate blood pressure after an effective heartbeat and ventilation have been established by other means.