Tips to Insure Quick Relief of Anaphylaxis Symptoms in Obese Patients

Subcutaneous injection of epinephrine for severe allergic reactions gives slower relief than intramuscular injection. Auto-injectors have needles too short to deliver epinephrine into the muscle for obese patients. This article gives tips for insuring quick relief from anaphylaxis symptoms with epinephrine in the obese.

Available Auto-injectors

EpiPen Jr. and EpiPen have ½-inch and 5/8-inch needles, respectively. The auto-injector in Twinject has a ½-inch needle. Shorter needles cause the epinephrine to be released subcutaneously rather than intramuscularly. Even in patients who are not obese, a one-inch needle is usually necessary to reach into the muscle. Giving epinephrine subcutaneously delays absorption up to 30 minutes.

Tip #1: If you are severely obese and have life-threatening allergic reactions, talk to your doctor about learning to use a syringe with a needle long enough to inject the epinephrine intramuscularly. Make sure you understand what dose of epinephrine to use, have the correct syringes, and know how to administer the intramuscular injection properly. Dosing errors and delays in preparing the injection can dangerously delay life-saving reversal of symptoms .

Tip #2: If your doctor advises you to stay with one of the auto-injectors, use the EpiPen since it has a longer needle than the one on the auto-injector in Twinject.

Tip#3: When using the EpiPen, press down firmly so that the fat under the skin is compressed, making it more likely to get the epinephrine into the muscle. Hold the EpiPen in place for at least 10 seconds.

Tip #4: Inject intramuscularly in the outer thigh for fastest delivery of a peak level of epinephrine.

Summary

Short needles in EpiPen or Twinject automatic injectors may not reach into the muscle in obese patients. This causes slower and less complete relief from anaphylaxis. Some obese patients may be able to safely draw up and give epinephrine intramuscularly using a one-inch or longer needle. Overweight patients who are advised by their doctors to stay with an auto-injector may choose the EpiPen over the Twinject since its auto-injector has a longer needle. Firm pressure against the thigh will depress the subcutaneous fatty layer of an overweight person and help deliver the medicine into the muscle.

DISCLAIMER: This article is provided for information only. This information is not a substitute for professional medical care by a qualified doctor or other health care professional. I am not responsible or liable, directly or indirectly, for any form of damages whatsoever resulting from the use (or misuse) of information contained in or implied by the information. This information is in no way intended as a recommendation of any drug therapy and is not intended as a diagnosis of any problem you may have.

SOURCES:

Stecher, D., Bulloch, B., Sales, Jr., Schaefer, C., Keahey, L. Epinephrine auto-injectors: is needle length adequate for delivery of epinephrine intramuscularly? PubMed.gov.

No author given. Epinephrine auto-injectors and needle length: can they deliver an
intramuscular dose? Pharmacist's Letter/Prescriber's Letter 2009;25(9):250904