A number of important studies have been conducted recently which relates to the inadequacy of the Epipen’s needle length when applied by certain types of patients who are suffering from anaphylaxis
Put simply the adrenaline from any adrenaline injector must be injected into a muscle. The problem is that the needle has to first pass through a layer of fat and for some people with a thick layer of fat, the needle simply does not penetrate sufficiently to reach the muscle. For over a quarter of women the Epipen needle length is not enough.
At the moment most auto-injectors have a needle the same needle length – around 15.2 mm – and in a recent study it was shown that of 100 patients, 19 patients were shown to have a fat layer greater than 15.2 mm and without exception all those 19 patients were women. The study goes on to show that some 28% of women are at serious risk of their adrenaline not being appropriately administered because of the higher than average levels of fat on their thighs.
In the US the recommended needle lengths for new borns are 16 mm, children between 1 and 12 years old 25 mm, and adults from 25 mm to 31 mm. In the UK the Resuscitation Guidelines recommend a 25 mm needle for all ages.
The Epipen and Jext autoinjectors do not meet the UK Resuscitation Council Guidelines with their longest needles being only 15.0 and 15.4 mm respectively. Insofar as needle length is concerned there is only one adrenaline auto-injector that appears to meet Resuscitation Guidelines – the Emerade.
Patients, and women in particular, should therefore make their prescribing doctor aware of these issues and insist that needle length be taken into consideration when prescribing their auto-injector.
This is an update to a blog I wrote in 2013 which lamented the fact that the adrenaline autoinjector models in the market (Anapen and the old Epipen model) carried needle lengths that might not deliver the adrenaline which an anaphylactic patient might need.
Two years later Anapen has disappeared from the market and Epipen has a brand new model, In addition two new autoinjectors have arrived in the UK, Jext and Emerade. Most people simply get a prescription from their doctor and get what they are given in the chemist but, just like buying a new pair of clothes, you should consider your choice of this life saving device very carefully.
We rarely question our prescribed drugs as they are taken orally and who are we, the unqualified patient, to question the choice of drug. In the case of these autoinjectors we should not question the life saving adrenaline but we should question the delivery method – the choice of autoinjector.
In a series of blog posts over the next few weeks I will be reviewing these three autoinjectors insofar as the following features are concerned:
- Needle Length
- Shelf Life
- Ease of use in an emergency
This website has no affiliation or personal interest with any of the manufacturers. I just want to make sure that all those with a serious allergic response leading to anaphylaxis have an effective autoinjector to hand and realise that these three delivery methods are not the same.
As consumers, we also have a choice!
David I Glaser
I know I may seem to go on and on about adrenaline auto-injectors, BUT they really worry me. These are life saving products and it is important that they work when they are used for whatever allergic reaction may happen.
So my interest in this article concerns needle length.
It is really important that the needle injects its life saving drug into the muscle of the thigh and a study in 2009 indicated that in fact a significant proportion of children did not have a long enough needle to reach the muscle the skin and fat. The same is undoubtedly true of adults because we all have different size thighs and yet the manufacturers of the auto-injectors provide a “one size needle fits all” solution to patients. Surely at the very least the length of the needle should fit the needs of the patient?
So if you have a large child or are a larger than normal adult and require an emergency adrenaline injector, such as an EpiPen, Jext, or Anapen, then please talk to your doctor and let us start putting some pressure on the manufacturers to provide the right solution for all patients and not just for some.
In short not only do we need different size of dosages but we also need different size needles, an option that is currently not available.
Article by David I Glaser
I am getting an increasing number of worried enquiries about how best to store adrenaline injectors in warm or cold climates. Does heat and cold make our Epipens, Jext and Anapen injectors inactive and potentially life threatening?
The manufacturers do have guidelines but they are fairly useless for the real world.
EpiPen say “You should take your EpiPen Auto-Injector everywhere you go, but it should be kept at room temperature (25°C, 77°F) until the marked expiration date, when it should be replaced” . Just how is someone meant to keep their EpiPens at this precise temperature and surely a range of temperatures would be more helpful. In their advice to professionals (not patients) it says:
“EpiPen and EpiPen Jr Auto-Injectors should be stored in the carrier tube provided at a temperature of 25ºC (77ºF); however, temperature excursions between 15ºC and 30ºC (59ºF to 86ºF) are permitted.”
Just what is a temperature “excursion” and how long does an excursion last? Suppose the safe temperature is exceeded? Are patients never allowed to go to the beach or play in the snow and just how are patients expected to maintain this temperature range?
Finally, why is the advice to professionals different to advice to patients?
David I Glaser