EpipenTM / TwinjectTM (unavailable 2016-??) -
epinephrine auto injectors
An automatic self-injectable
epinephrine unit (auto injector) has been prescribed for you or your child.
A mild allergic reaction – a few hives or slight swelling under the skin – can
be treated with antihistamines [ReactineTM(ceterizine), ClaritinTM(loratadine),
AeriusTM(desloratadine), or AllegraTM(fexofenadine)]
and close observation for 12 hours. Older sedating antihistamines, BenadrylTM (diphenhydramine) and ChlortripolonTM
(chlorpheniramine), are second best choices due to sedation, and memory-motor
impairment. An antihistamine should always be kept with your auto injector – 2
tablets under the cap in saran wrap for adults, or a small attached container
(with the correct liquid dose) for young children. The appropriate
antihistamine dose for an acute allergic reaction is double (2 times) the
standard dose. AeriusTM liquid and ReactineTM
liquid are better tasting.
A moderate to severe
reaction – hives all over, large
or widespread swelling of the skin, any difficulty breathing, dizziness or
fainting, and any combination of 2 different body systems, [examples would be
the development of hives (the skin) plus any chest symptoms (respiratory
system), or vomiting or diarrhea (gastrointestinal system), or headache
(nervous system), or severe weakness (the cardiovascular system), and so on],
should be immediately treated by injecting epinephrine into the upper outer
thigh, then taking an oral antihistamine (and possibly prednisone to blunt
late phase reactions), then immediately going to the nearest emergency
department by the fastest-safest route. Dizziness, feeling faint, and frank
unconsciousness, should be treated additionally by immediately laying flat and
then elevating the legs above the rest of the body to allow proper blood flow
between the heart and the brain. Young children should always lay flat prior to
receiving their epinephrine injection so they cannot move their leg away from
the needle. ONLY using injectable epinephrine EARLY can reduce the risk of a
severe multisystem reaction and the risk of a delayed (LPR) reaction.
Every time epinephrine is
used you must be medically assessed and observed for 12 hours for the
possibility of developing a late phase reaction (can occur up to 12 hours
(rarely later) after initial reaction), which will require additional
treatment. Antihistamines and prednisone may be required for several days after
the initial reaction.
Every child should carry
their auto injector on their person at all times, even if they require an adult
to administer the actual injection.
Speed of administration is essential (if the epinephrine is not with the
allergic patient it may be too late). The earlier epinephrine is given, the
more effective it is in preventing further allergic-anaphylactic symptoms. The
use of epinephrine is safe, causing a mild tremor and increased pulse rate for
15 to 20 minutes. If in doubt - give epinephrine!!! Using epinephrine is appropriate for all
anaphylactic reactions regardless of other medical conditions (the risk of
anaphylaxis is greater than the risk of heart disease, etc.)
Further doses of epinephrine
can be safely given every 15 minutes in the case of prolonged reactions.
(Antihistamines given after the first dose of epinephrine, take 30 to 60
minutes to take full effect, and only counteract part of the allergic
reaction). Therefore, if you are a long way from the nearest emergency
department (i.e. camping or working in the bush) you should have several auto
injectors. The minimum would be 3 or 4
doses of epinephrine to allow your antihistamine to take effect. Antihistamine prophylaxis (taken prior to
possible exposure) is strongly recommended-see the section on Anaphylaxis.
In severe reactions where the individual is
clearly getting worse 5 minutes after initial injection, an additional injection
can be administered. Approximately 30% of allergic reactions will require a
double dose of epinephrine to control initial symptoms.
Although the severity of the individual’s
allergy can influence the dose of epinephrine prescribed, in general, if the
individual is less than 25 kg. (55 lbs.) use the 0.15 mg dose (Junior) ; and if
over 20 kg. (66 lbs.) use the 0.3mg dose
(Adult) .
A Medic AlertTM
must be worn by the allergic-anaphylactic individual at all times. Many teens
and adults do not do this and put themselves at risk for misdiagnosis and
incorrect treatment of their reaction. (An adult could be treated for a heart
attack instead of anaphylaxis if the emergency personnel had no idea that an
acute allergy reaction was possible).
-numbness, itching, mild
hives or mild swelling - take antihistamine (double regular dose) AND OBSERVE
CLOSELY FOR 12 HOURS
-generalized (head to toe)
large hives, large or generalized swelling, any breathing problems, passing out
(fainting), any combination of 2 systems, or rapid onset of any of the above, IMMEDIATELY INJECT epinephrine into the outer upper
thigh, then take an oral antihistamine if available while starting to head
to the nearest emergency department by the quickest and safest way.
FURTHER NOTES :
EpiPenTM
(www.epipen.ca
)
When the EpiPenTM
is injected into the upper outer thigh remember the following points:
-grip the pen with the entire
hand (never finger tips)
-get completely ready,
holding the Pen over the outer upper thigh, before removing the grey safety cap
on the top of the Pen (to avoid inadvertent triggering)
-firmly strike the Pen at a
right angle against the thigh (this triggers the needle) and hold against the
thigh for 5 full seconds to allow the epinephrine to be injected)
Practice with a dummy Pen several times
initially and monthly thereafter. You can make your own dummy with a similar
sized stick and plastic cap on one end. This technique must be learned so there
is no hesitation OR error in this technique. Only repetitive practice
accomplishes this.
The needle will penetrate through regular
pants.
The
expiry date on the EpiPenTM should be noted. You
should always carry an up to date Pen. Outdated Pens retain some residual
potency for 1 to 2 years, but can only be considered as emergency back ups by
those who cannot afford multiple up to date Pens.
These devices should not be frozen or
exposed to extreme heat. If this is suspected the Pen should be replaced. If
the clear solution in the Pen (visible in the middle of the EpiPenTM)
becomes cloudy, the Pen should immediately be discarded and replaced.
TwinjectTM
(not available since 2016 due to dose delivery problem, not sure when
will be available again)
The administration of the first dose of Twinject is identical to that of the EpiPenTM
except top and bottom caps must be removed prior to use. The administration of the second dose of Twinject is completely different, requiring the individual
administering this dose to unscrew the tip of the Twinject
auto injector, remove a syringe from inside the auto injector, and use this
syringe to administer the second dose of epinephrine. Please go to the TwinjectTM web site www.twinject.ca
or www.twinject.com to view a
demonstration of how to use this device and to obtain a free practice auto
injector.
CAUTION
One of the largest problems with the use of
auto injectors has been the reluctance/fear of individuals to give themselves
the injection. Part of this is based on
inadequate knowledge of when to use and hesitancy to take any medication. But a huge part of this is based on the fear
of using a needle. Fear of needles is
extremely widespread and many individuals (particularly adults) actually deny
that they have this problem. The bottom
line is that many individuals do not use their auto injector when required.
Many studies have shown this, including deaths that could have been avoided. Do not under estimate this fear - a
significant number of individuals would rather risk death than use an auto
injector. Patients must understand that the treatment for anaphylaxis is
EARLY use of injectable epinephrine.
The wonderful thing about the EpiPenTM and TwinjectTM (first
dose) is the patient does not see the needle at all until after the injection
is complete (and the auto injector is removed from the outer upper thigh and
put back in its plastic container).
The drawback to the TwinjectTM
is the second dose requirement. The
individual administering this second dose has to remove the needle-syringe from
the auto injector and then inject this needle-syringe into the outer upper
thigh again to obtain the second dose.
This is a huge problem for the majority of individuals (as it has proven
difficult to get individuals to use the first dose). In essence, you need to be taught two
techniques to use the TwinjectTM. The good points about the TwinjectTM
are a smaller auto injector container which contains 2 doses of epinephrine
(needed in 30% of cases) and costs approximately $100.
The drawbacks to the EpiPenTM
are at least two separate auto injectors are required (bulky) and each will
cost slightly over $100.
I
usually prefer to prescribe the EpiPenTM because of
the difficulties addressed above in self administering epinephrine. I have prescribed the TwinjectTM
to individuals who are competent in understanding and administering two
different techniques (such as health care workers, diabetics on insulin, etc.).
Useful web sites: Medic Alert
at www.medicalert.ca
AAIA Allergy
Asthma Information Association at www.aaia.ca
(AAIA has
an Epipen training kit with dummy pen and training
material)
Anaphylaxis
EpiPen www.epipen.ca trainer & educational material
Dr. Bruce Sweet, 2017