|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.