Epinephrine for Emergency Self-Administration

Epinephrine for self-administration is vital for patients with a history of anaphylactic reactions.  Such patient should be given a prescription for an emergency epinephrine kit or syringe, and the patient (or parent) should be instructed in proper administration of the drug.  The kit or syringe should be readily available at all times.  Exposure to air and light can cause the epinephrine to oxidize and turn brown, at which point the syringe should be replaced.

Epinephrine for emergency self-administration is available in several forms.  The Ana-Kit (figure 1) contains a syringe (Ana-Guard Epinephrine), tourniquet, chlorophreniramine maleate tablets, and an alcohol swab.  The syringe has a 25 gauge needle and is operated manually, so there is little chance of accidental injection.  A maximum dose of 0.3 mL of 1:1,000 epinephrine can be delivered at once, and graduations on the syringe barrel allow delivery of smaller doses for children.  A second 0.3-mL dose can be delivered if symptoms do not improve.



EpiPen Auto-Injector (figure 2) is self-injecting syringe that automatically delivers a single 0.3-mL dose of 1:1,000 epinephrine. (A pediatric version, EpiPen Jr., dispenses 0.3 of 1:2,000 epinephrine.) This device is popular among patients who are uncomfortable injecting themselves. It has been useful in schools and daycare facilities, where trained personnel may not be available.  It is simple to use and requires a force of only about 3 lb to the tip to trigger the injection mechanism. However, caution must be used to avoid accidental injection.  The 22-gauge needle is propelled by a spring that generates 16lb of force; this could be problematic if the needle were to hit solid tissue such as bone.