Indications
Norepinephrine (also called noradrenaline) is an emergency and intensive care medicine used to raise and maintain blood pressure in adults with dangerously low blood pressure (shock), such as septic shock, or low blood pressure that persists despite adequate fluid replacement, for example after a heart attack or during anaesthesia. It is given only by a doctor or nurse in hospital, usually in an intensive care unit.
How It Works
Norepinephrine is a natural hormone and nerve messenger. It acts mainly on alpha-adrenergic receptors in blood vessel walls, causing the vessels to narrow, which raises blood pressure. It also acts on beta-1 receptors in the heart, supporting the force of heart contraction. Higher blood pressure improves blood flow to vital organs such as the brain, heart and kidneys.
Dosage and Administration
It is diluted, usually in Glucose 5% solution, and given as a continuous infusion through a large vein, preferably a central venous line, using an infusion pump. The rate is started low and adjusted by the medical team minute by minute according to blood pressure, which is monitored continuously. It is reduced gradually, not stopped suddenly.
Interactions
MAO inhibitors, such as Linezolid, and tricyclic antidepressants like Amitriptyline can greatly increase its effect and cause severe high blood pressure. Some anaesthetic gases can make the heart more prone to rhythm problems. Other medicines that narrow blood vessels or raise blood pressure, and Digoxin, can increase the risk of side effects. Beta-blockers may alter its effects. The ICU team manages all of these.
Contraindications
- Low blood pressure caused mainly by uncorrected low blood volume (fluids should be given first), except as an emergency measure.
- Known allergy to Norepinephrine or any ingredient, including sulfites in some products.
- Use with certain anaesthetics, such as Halothane or Cyclopropane, because of rhythm problems, unless judged essential.
Side Effects
Possible effects include headache, anxiety, slow or fast or irregular heartbeat, chest pain, high blood pressure, breathlessness, and cold hands and feet due to narrowed blood vessels. If the infusion leaks out of the vein, it can damage the surrounding skin and tissue. Reduced blood flow to fingers, toes, gut or kidneys can occur with high doses.
The medical team watches for and treats these at once. Patients or family should tell staff immediately about chest pain, severe headache, pain, swelling or colour change at the drip site, or fingers and toes turning pale, blue or very cold.
Pregnancy and Lactation
It may reduce blood flow to the womb and is used in pregnancy only when the benefit for the mother clearly outweighs the risk, which is often the case in life-threatening shock. It is not known if it passes into breast milk; the doctor will advise on breastfeeding.
Precautions and Warnings
- Requires continuous monitoring of blood pressure, heart rhythm and urine output.
- Low blood volume should be corrected before or during treatment.
- The infusion site is checked often to prevent leakage injury.
- Use with care in people with heart disease, narrowed arteries, diabetes, or an overactive thyroid.
Overdose
Overdose can cause severe high blood pressure, very slow heartbeat, headache, chest pain, bleeding in the brain and poor circulation to the limbs. It is managed in hospital by reducing or stopping the infusion and giving treatment as needed.
Therapeutic Class
Vasopressor; adrenergic (sympathomimetic) agent.
Storage
Store as directed on the pack, usually below 30°C, protected from light, in the original carton; do not freeze. Do not use if the solution is brown or contains particles. Kept by hospitals, out of the reach of children.
Prepared by the Oshud Alo team from standard drug references. For information only; always follow your doctor's advice.