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Pressurized "Jet" Injectors Fact Sheet

I have personally tested all models available as of June, 1996.
I am not affiliated with any manufacturer.
I welcome your comments, corrections & questions.

Jet injectors require cleaning every 2-3 weeks, a willingness to
learn how to use them, and some body fat to inject into.

Both adults and children use them, although some people cannot,
citing painful injections and bruising or bleeding at the injection
site. On the other hand, many users, myself included,
have no pain, no bruising, and only an occasional pinpoint spot of
blood at the injection site -- and I inject 3-5 times per day.

Clearly, YMMV (Your Mileage May Vary).


Jonathan Mills
Associate Professor
Computer Science Department
Indiana University
Bloomington Indiana 47405

Manufacturers in alphabetical order
The first telephone number given is the business number. Some
overseas locations can't reach 800 numbers (but if you can, use the
800 number and save the charge).

Medi-Ject Corporation
1840 Berkshire Lane
Minneapolis  Minnesota  55441 USA

Models:   Medi-Jector EZ        US$ 595 (50 units maximum, new design 1996)
          (Children's model available with smaller nozzle)

Moore Industries, Inc.
Medical Technologies Division
185 E. North Street
Bradley  Illinois  60915 USA
(You may be referred to a distributor.)

Models:   AdvantaJet           US$749 (50 units, RN/LPN trains you in person)
           GentleJet           US$749 (Children's model)

These models have been called a variety of names.  Basically, these are
all the same unit:  PreciJet, Freedom Jet, Freedom System, AdvantaJet,
GentleJet.  However, a new model is reportedly under development.

Vitajet Corporation
27075 Cabot Road
Suite 102
Laguna Hills  California  92653 USA
(You may be referred to a distributor.)

Models:   Vitajet II            US$1000 (50 units, price approximate)

Injectors in the order I tested them & wrote this sheet

                Medijector EZ   VitaJet         AdvantaJet (Freedom Jet)
                -------------   -------         ------------------------
cost            $595            about $1000     $749

training        video           video           nurse comes to your home

                user's manual   user's manual   user's manual

dosage          2-50 units      2-50 units      2-50 units

settings        15              12              12

adjusted?       backoff twist   change internal backoff twist
                                pressure rings

easy to wind?   moderate         moderate        moderate
                (new grip is     (grip has       (grip has
                larger)          'wings')        'wings')

reliability     excellent       good            excellent
                                'crystal check'
                                chamber ring
                                should be
                                replaced every
                                3 months)

trial period    30 days         30 days         30 days

clean?          every 2 weeks   every 2 weeks   every two weeks

how?            wash then       soak in alcohol soak in alcohol
                boil 20 min     for 20 min      for 20 min
                to sterilize

injection       'snap' to       'snap' to       'snap' to
                slight pain     slight pain     slight pain

                (Sensation depends on dosage & site & subcutaneous fat: the
                more fat, the larger the dose that can be injected painlessly
                I have tested all with up to 30ml of saline in my outer thigh
                and have had no pain, only a slight discomfort (stinging). In
                daily use the mediject & the vitajet produce no pain, but the
                mediject is easier to adjust for different pressure settings
                for different sites (arm, thigh, stomach, buttocks). I found
                that starting with the injector (having never used insulin
                before) I would get large raised lumps, due I now believe
                to a local allergic reaction to the preservatives in the
                insulin.  After a couple weeks they went away, but until they
                did I was liable to get a yellow-green bruise a day after
                the raised lump, and at that site.)

frequency       1-5 times per day for most users
of injection

easy to read    small numbers    big numbers     big numbers
                (easy)           (very easy)      (very easy)

recommend       no              yes             yes
for arthritic
or sight-
impaired users?

recommend       no              no             no
for extremely
thin users?

combine dosages yes             yes             yes

restrictions    ultralente      ultralente      ultralente
                may clog        may clog        may clog
                nozzle, clean   nozzle, clean   nozzle, clean
                more often      more often      more often
                (do not use
                with the
                tender touch)

                load r before   load r before   load r before
                nph/ultra       nph/ultra       nph/ultra

available       no              yes             no
prescription    (don't ask me why the vitajet isn't, I don't know)

cost covered    50-90%          50-90%          50-90%
under insurance
as 'durable
medical equipment'

                (Note that many MDs and CDEs base their opinion
                of injectors on their performance 10 years ago -- and they
                have improved dramatically since then. You may have to be
                VERY pushy to get your MD or CDE to agree to let you use
                a pressurized injector).

other equipment vial adapters   vial adapters   vial adapters
                6/$18, not      ?               ?

                -               crystal check   -
                                chamber rings

                (All come with a pocket wallet to carry the injector and
                a couple vials of insulin, and vial adapters and caps. All
                also come with sterile saline to practice your technique. The
                vitajet comes with spare o-rings, crystal check chambers, and
                pressure-setting rings.  The medijector includes small plastic
                tools to remove the injector head for cleaning.  the advanta-
                jet has a very nice small case for daily use, a larger case
                for travel use, and a cleaning/soaking stand)

General comments

1. Bruising.  The advice from all manufacturers if you have shallow
bruising is to INCREASE THE PRESSURE SETTING (fewer back-off clicks).

In my experience, having started with the injector at the same time
as I took insulin, and being careful to follow the instructions
AND to practice with saline first for a few days, and based on a
statistically insignificant number of other users:  it will take a
few weeks to adapt to the insulin.  Even humulin is not 100% pure
human insulin.  Once your body is used to the preservatives and
carriers -- which are far more evenly distributed with a pressurized
injection, and so more likely to cause a local allergic reaction in
the skin -- the bruising will stop.  Stick with it.

(After two years:  no more welts after those first few weeks.  My
suspicion is that it was a brief allergy to the preservatives, and
that it had nothing to to with small variations in injection
technique -- the injector seems to be forgiving of such tiny error)

2. Deep bruising.  If you have deep bruising then DECREASE THE
PRESSURE SETTING (more back-off clicks).

Deep bruising is usually accompanied by a large drop of
blood or bleeding at the injection site for several
seconds.  The injection may have been painful.  A small
dark purple bruise, perhaps 1 inch (2.5cm) in diameter,
forms later at the injection site. Decrease the pressure
setting.  If you've been pretty consistent in your
technique, you probably forgot to adjust the back-off
clicks entirely.  I've done it myself.

3. 'Wet' injections.  If the injection site is wet, and has a 'puddle'
of insulin afterwards, the pressure setting was probably too light.
Increase it.

But, if you have been using your injector for several months, and
are not rotating sites (a benefit of the injector) and didn't make
a mistake on your settings or change your dosage amount...then check
the inside of your vial adapter.  Changes in atmospheric pressure or
temperature can cause the insulin in the adapter to bubble out as
you load the injector, and leave the injector head holding enough
insulin to wet your skin.  Since an injector has enough strength
to shoot a stream of insulin through your clothing and into your
leg if you activate it accidentally (experience speaks here), the
odds are that the injector head was wet.  But check your dosage,
pressure settings, vial adaptor, etc. at your next injection to
be sure nothing has changed.

4. Cleaning and Sterilization.  Isopropyl alcohol may or may not
sterilize an injector.  The manufacturers argue about this, and
I could not get a definitive answer from the physicians I asked.
For best results, do NOT share your injector, and DO follow the
manufacturer's guidelines.

Having said that, I will also say that I now clean and sterilize
the medijector only 3-4 times per year, and it works fine.  In part,
this may be because I use mostly R insulin, which does not clog the
orifice.  YMMV.  Keep track of your injections if you choose to
do this:  a series of shallow or deep injections may be due to a
clogged injector or crystallized insulin inside the injection
chamber (and no, this is unlikely to be a problem during the first
month or two of use).

Reprinted with permission of Jonathan Mills

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Last Updated: Thursday February 27, 2014 19:28:20
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