August 12, 2018

How to Use Epinephrine for Anaphylaxis?

An injection of epinephrine (adrenaline) is an essential part of the treatment of an anaphylactic reaction. This hormone should be given to a person immediately, in case of any symptom of anaphylaxis, even when the cause of the reaction is not clear.

 

There are two methods of epinephrine administration: intramuscular and intravenous. Depending on how severe the reaction is, people use the first or the second method. If a patient is experiencing a severe anaphylactic shock, intravenous administration may be required.

However, intramuscular administration is more common. 0.3 to 0.5 cc is the dosage in an adult, and the standard intramuscular dose comes in a 1:1,000 concentration. If a child has an anaphylactic reaction, the dose should be lower – 0.01 mg per kg. Epinephrine is injected into the lateral aspect of the thigh.

If a patient doesn’t respond to the medication, the dose can be given repeatedly up to three or four times, every 5 to 15 minutes.

However, sometimes, even repeated intramuscular injections may not be effective, especially if the patient seems to experience a complete cardiovascular collapse. In this case, the medication should be administered intravenously. Normally, adequate cardiovascular monitoring of the patients is required, if epinephrine is administered intravenously. There still might be exceptional circumstances though.

When it comes to intravenous epinephrine administration, no standard dose or regimen have been established yet. The only thing that is for sure is that the standard concentration for intramuscular administration is not suitable for intravenous injections. If epinephrine is administered intravenously, the concentration should be more diluted.

There have been various recommendations concerning the regimen, but they have never been tested against other people.

One of these recommendations suggests that a solution for intravenous administration should consist of 1 mg (or 1 ml) of a 1:1,000 epinephrine concentration added to 250 ml of dextrose 5% in water. The initial infusion rate for such a solution should be 1 mcg per minute. This rate may vary, depending on the clinical response.

It is important to remember that intravenous administration of epinephrine is associated with the risk of lethal arrhythmias, which is why this method of administration is only suitable for patients with very low blood pressure or those who experience cardiorespiratory arrest and fail to respond to intramuscular injections. As mentioned earlier, cardiovascular (or hemodynamic) monitoring is highly recommended, if the medication is administered intravenously.

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