Thank you for your inquiry.
Epinephrine should be given at the first sign of anaphylaxis regardless of cause. The decision as to whether or not to administer epinephrine via intramuscular or intravenous administration depends upon the severity of the episode, and of course, whether or not the patient is in shock, which may make intravenous administration necessary.
However, in most instances, epinephrine can be administered intramuscularly. The dose in an adult is 0.3 to 0.5 cc. The standard intramuscular dose is a 1:1,000 concentration. This should be given in the lateral aspect of the thigh by intramuscular injection. The dose can be repeated every 5 to 15 minutes, depending upon the response, for three to four doses. The same is true for children except the dose is 0.01 mg per kg.
If the patient does not respond to three to four doses of epinephrine intramuscularly, or if, according to the judgment of the individual caring for this patient, there is complete cardiovascular collapse, a decision to administer intravenous epinephrine should be made. However, intravenous epinephrine should be given in most instances only when the patient is under adequate cardiovascular monitoring.
Unfortunately there is no established dose or regimen for intravenous administration. Many regimens have been recommended, and none, to my knowledge, have been tested against others.
The one thing that must be avoided is the administration of the standard 1:1,000 concentration given for intramuscular injection intravenously. Intravenous administration always utilizes a more dilute concentration.
As noted, there are many different suggested protocols for the administration of intravenous epinephrine. One is to add 1 mg (1 ml) of a 1:1,000 concentration of eponephrine to 250 ml of dextrose 5% in water. This solution could then be infused at an initial rate of 1 mcg per minute. The infusion rate is varied according to the clinical response.
As noted, because of the risk of potential lethal arrhythmias, epinephrine should be administered intravenously only in profoundly hypotensive patients or patients in cardiorespiratory arrest who have failed to respond to intramuscular epinephrine and volume replacement. It is highly desirable to have hemodynamic monitoring in place when using intravenous epinephrine..
Thank you again for your inquiry and we hope this response is helpful to you.
Phil Lieberman, M.D.