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                      Medijector FAQ

                           by
                      Thomas Albright
                  albrigh@ucs.indiana.edu
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 Note: This is a copy of a post to the diabetes listserve group. It
 is not in question-and-answer form, though it answers many questions
 about the use of injection guns.
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There was a discussion of injection guns on m.h.d. a few weeks ago, but 
it died out pretty quickly. I have the impression that few people use 
them, or that those who do use them don't participate in these 
electronic forums. Then again, there are at least two manufacturers, so 
they must have customers. In those discussions, basically it turned out 
that people either had good experiences with guns and REALLY liked 
them, or had bad experiences and REALLY hated them. I am one of those 
who REALLY likes mine.

I became Type-I in 1985 at the age of 32. I used needles and syringes 
for about two years, and then I heard about needle-less injection guns 
at a diabetes seminar sponsored by the Hooks Drug Store chain. I took 
home all the information and looked up a research report -  I was 
convinced. After confirming that my health insurance covered the unit, 
I bought one. I got the Medijector-II model (since then, newer models 
have come out, such as the Medijector-EZ). At the time, my unit sold 
for $800, of which insurance covered 80%. By the way, you do have to 
have a prescription from your physician to get one and for insurance to 
cover it. The rep at Hooks Convalescence Center in Indianapolis, where 
I bought it, gave me a thorough demonstration and promised to send me a 
training videotape, but I never received the tape. The instruction 
booklet turned out to be sufficient to teach me how to use it, however.

Setting the correct dosage with my model, the Medijector-II, is a 
little complicated until you understand the mechanics of it, and I 
think it would be too much for children or the very elderly to deal 
with. Supposedly, the Medijector-EZ took care of that, but I have no 
experience with that unit. The company that makes these is the 
Medijector Corporation in Minneapolis. My unit came with a 5 year 
warranty and has a projected life of 20 years. I have heard that there 
is another company that makes injection guns, but I don't know anything 
about them, who or what or where.

The gun is roughly cylindrical, an inch+ in diameter, and about 6 
inches long. On the injection end is a removable valve-body, piston, 
and spray nozzle. The spray nozzle has a hole 1/3 the diameter of a 
human hair. The valve-body is periodically removed from the gun to be 
cleaned and sterilized by the user. On the other end is the release 
button and a winding sleeve. The winding sleeve is used to set the 
dosage, and as it is turned it winds up a spring which powers the unit.  
Insulin vials must be mounted in special plastic containers which clamp 
onto the nozzle. To load insulin into the gun, one fits the 
insulin/container onto the nozzle, and then turns the winding sleeve - 
this draws the piston down, sucking insulin into the valve chamber. To 
complete the injection, you dismount the insulin vial, hold the gun to 
the injection site, and press the release button. The spring pushes the 
piston, and the insulin is sprayed out the nozzle and through the skin.

The insulin is not deposited in a pool as is the case with needles; 
rather, as the spray moves from layer to layer of skin, it fans out, 
thus saturating the tissue. In a study done at Mayo (I don't have the 
reference at hand but can get it), it was shown that this delivery 
resulted in quicker and more even absorbtion. For a few seconds after 
the injection, the tissue at the site is clearly saturated - slightly 
raised skin about the size of a dime, and a little light in color. Most 
of the time, there is a tiny spot of blood. (A little bit is okay, and 
I just use a band-aid to keep it from spotting my clothes, but more 
than a little bit means the pressure needs to be lessened. One learns 
to adjust accordingly.) By the way, the presence of blood does not mean 
that you have injected into a blood vessel (which is a no-no with 
needles), but rather that you have clipped a capillary and the insulin 
still saturates the tissue AROUND the site. A little pressure to the 
site stops any bleeding. The injection pressure is adjusted by turning 
the winding sleeve. Too much pressure means a deep injection and 
bleeding; too little pressure and not all the insulin goes in (this is 
called a "wet injection"). I have a wet injection about once a month or 
less. In such a case, I just assume that about half of the insulin 
didn't go in and give myself another half-dose (and then watch myself 
that day).

In my experience, about half the time I feel next to nothing. A quarter 
of the time I feel a little sting, and another quarter of the time it 
just plain hurts. I hate needles, and they almost always hurt me, so 
when I first got my gun I really loved it. Then I began to encounter 
problems, and I really lost all faith. But as time went by I learned 
how to adapt its use and once again really love it. Here are some 
examples of what I mean. When I inject in my thighs and buttocks, I 
have little or no pain, only a little bruising, and very few wet 
injections. When I would inject in my abdomen, it would really sting 
and I would get huge, painful welts - enough to make anybody hate the 
gun. Maybe some people can inject in the stomach, but I have learned 
that I can't. When I would inject in my upper arms, I would almost 
always have wet injections - my skin is too tough - and this is 
unacceptable. So I only use my legs and buttocks. I use my right side 
for my morning shot and my left for my evening shot. Sometimes some 
bruising develops, and I just give that sub-area a month's rest.

When the unit was four years old, the mechanism jammed. I sent it by 
over-night express to the factory for repair under warranty. It was 
back in less than one week. It has jammed twice more since then, and if 
the pattern continues, it will do so every one or two years. Now that 
the warranty is out, it has cost $80 each of the two times for the 
repairs. Of course, it's a real hassle when it breaks: it means 
spending half a day to prepare, package, and ship it, and run around 
getting fresh insulin and syringes to use in the interim.