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| Equipment for measuring blood and urine glucose in veterinary patients. |
Aside from requiring
insulin injections twice a day, diabetic animals must be monitored closely,
treated for comorbidities such as urinary tract infection and cataracts, and
fed consistently. Veterinarians are often required to troubleshoot poor
glycaemic control, which may be due in part because of the way insulin is
administered. Better glycaemic control means fewer complications and better
quality of life for diabetic patients.
So I was fascinated to
learn more about insulin dosing pens via a webinar presented by Dr Linda
Fleeman. Dr Fleeman runs Animal Diabetes Australia, a clinical service designed
specifically for diabetic dogs and cats, across three veterinary practices in
Melbourne.
Insulin dosing pens are
commonly used in human patients, but they’re not widely used in veterinary
patients within Australia. They deliver a more accurate and precise dose than
an insulin syringe, which is really important when we are talking about very
small volumes (in some cases 0.5U). With syringes, the dose delivered often
exceeds the intended dose – one study found that when people thought they were
drawing up 1U, they were drawing up anywhere between 0.6 and 2.8U!
So the first thing I
learned was that insulin pens deliver a much more accurate dose.
According to Dr Fleeman,
insulin pens are adopted much more readily than syringes and needles. Clients
are more familiar with these (they are used for human diabetic patients, people
receiving IVF treatments etc). Dr Fleeman also reported that these injections
are less painful.
Currently available
insulin pens within Australia are all designed for human patients, but a
veterinary specific pen (VetPen) will soon be on the market. One pen will
deliver increments of 0.5U to a maximum dose of 8U, while the larger pen gives
doses of 16U at 1U increments. This is designed for use with U40 insulin.
They last for a while, perating
for around 3000 uses (at 2 injections per day or 1500 days it would last around
four years). Needles are changed daily.
As glargine is the first
insulin choice for diabetic cats, the Lantus Solostar pen can be used. This is
a disposable pen containing 3ml of insulin which can be ordered for feline
patients.
The second thing I learned is that the most important thing
to remember is that pens need to be primed before every single injection. To do
this, the client needs to dial up a specified amount (usually 1-2U) then fire
off the dose). With a new pen you may need to do it 5-6 times before insulin
comes out.
When troubleshooting poor
glycaemic control in animals being treated with insulin pens, veterinarians
need to remember to ask how and how often the pen is primed.
It is important that the
right insulin is used for the right pen to ensure the correct dose is delivered
(i.e. pens are designed to fit specific insulin cartridges).
Insulin dosing pens do not
need to be kept in the fridge which means they are easy to travel with. They
should be kept away from light and below 28 degrees Celcius.
The way Dr Fleeman teaches
people to time their insulin dose is to count to four. On one you lift the
skin, two insert the needle, three depress the button and on four remove the
needle. They may be a drop of insulin on the tip of the needle afterwards –
this is normal.
When choosing needles,
12mm needles are best for dogs and cats.
Needle-less insulin
delivery systems are available but the cost is prohibitive at this stage.
One other thing that I
learned is that new research is emerging that occult UTI in diabetic human
patients may be protective against infection with more pathogenic agents. That
is, if urinalysis does not reveal inflammation it may not be beneficial to
treat these patients with antimicrobials.
