Why Does EpiPen Have to be Injected into the Thigh?

As any severely food allergic patients know, when suffering from a potentially life-threatening anaphylactic reaction, they need to jab an epinephrine needle into the side of their thigh...

But... why the thigh? Why not the arm like most other shots?

Per AAAAI, there have been 3 anatomic sites investigated to determine which location offers the fastest systemic absorption of epinephrine when injected intramuscularly and/or subcutaneously.

• Intramuscular injection in the upper arm (deltoid muscle) just like a flu shot.
• Subcutaneous injection in the upper arm just like an allergy shot.
• Intramuscular injection in the lateral thigh (vastus lateralis muscle).

Of these sites, the intramuscular thigh injection demonstrated the fastest rise in blood epinephrine.

When dealing with a life-threatening anaphylaxis, you need the speed because if the drug is too slow, the person may die before adequate epinephrine levels are achieved... and the thigh muscle provides the speed whereas the other sites do not.

Why might that be?

It's probably because the thigh muscle is large with lots of blood vessels allowing for multiple points of access for the injected epinephrine to enter into the blood circulation.


References:
Epinephrine absorption in children with a history of anaphylaxis. J Allergy Clin Immunology 1998; 101(1):33-37.

Epinephrine absorption in adults: intramuscular versus subcutaneous injection. J Allergy Clin Immunol 2001; 108(5):871-873.

An All-Natural Deadly Insecticide But Non-Toxic (& Drinkable) to Humans

It's about TIME!!! I read this fascinating story on NPR here.

An all-natural insect repellant called nootkatone found in Alaska yellow cedar trees and citrus fruits (like grapefruit) is being developed by the CDC. It is so safe for humans, it is even an FDA-approved food additive.

Nootkatone is not only safe for humans and the environment, it is a highly effective insect repellant. In fact, it is not only a bug repellant, but an insecticide causing death to biting insects like mosquitoes within 15 seconds.

Application of 2% nootkatone will also control ticks for up to 42 days at greater than 97 percent efficacy.

It is non-greasy, dries very quickly, and it has a very pleasant, citrus-y grapefruit odor to it.

Sounds too good to be true... But it is true! The only downside right now is that it is not available in the market, mainly because it is expensive — $4,000 per kilogram for highly purified food-grade material, which is used in parts-per-million amounts as a flavoring agent.

However, there are two companies that are currently working to make it available as insect control, hopefully in the near future!

Read more about this here.

References:
Susceptibility of four tick species, Amblyomma americanum, Dermacentor variabilis, Ixodes scapularis, and Rhipicephalus sanguineus (Acari: Ixodidae), to nootkatone from essential oil of grapefruit. J Med Entomol. 2011 Mar;48(2):322-6.

Mode of action for natural products isolated from essential oils of two trees is different from available mosquito adulticides. J Med Entomol. 2010 Nov;47(6):1123-6.

Ability of two natural products, nootkatone and carvacrol, to suppress Ixodes scapularis and Amblyomma americanum (Acari: Ixodidae) in a Lyme disease endemic area of New Jersey. J Econ Entomol. 2009 Dec;102(6):2316-24.

Use of novel compounds for pest control: insecticidal and acaricidal activity of essential oil components from heartwood of Alaska yellow cedar. J Med Entomol. 2005 May;42(3):352-8.