I’ve generally used a U-40 insulin (PZI-Vet) with U-100 syringes. The advantages being that U-100 syringes are more widely available, and by using U-100 syringes with U-40 insulin I was able to make smaller dose adjustments. (Before Meow Meow went off insulin, she was getting 0.2 units (two-tenths of a unit) of insulin! NOT TWO UNITS – two-tenths of a unit! No way I could measure that amount using a standard match of syringe to insulin.
Many find converting insulin to a different syringe confusing – and if, for that reason, you want to match – GREAT! I recommend ALWAYS checking to make sure you KNOW which syringe and which insulin you’re using. I’ve seen disasterous results when people don’t, and aren’t working with what they think they are. Some insulins come in different strengths (like compounded PZI) and syringes obviously come in various markings – and there have even been cases where syringes were in the wrong box! ALSO – make sure you understand whether your syringe is marked only for whole units, or also half units! I’ve seen people advise others to count “lines” – well, whether you have lines only for whole units or whole and half units can DOUBLE YOUR DOSE!
Let’s assume you DO want to use a U-40 insulin (PZI-Vet, Vetsulin/Caninsulin, etc) with a U-100 syringe. Converting isn’t that difficult.
1 unit of U-100 insulin = 1 unit of U-40 insulin. Units are units.
The difference is the volume of liquid needed for that unit. There is 100 units in every 1 mL of liquid of U-100 insulin. There are 40 units per mL of liquid in U-40 insulin. Fewer units in U-40 insulin = less concentrated.
It’s like the difference between buying laundry detergent that’s concentrated – the “cap” which you fill with detergent per load of laundry is smaller the more concentrated the detergent is. So, if you have concentrated detergent, you use one cap from that bottle. If you have detergent that’s not concentrated, you use one cap from that bottle – but the cap is larger so you’re using more detergent. So if you lose the cap off your non-concentrated bottle of soap and have to use the smaller cap off your concentrated bottle of detergent, you may need to use 1.5 caps of soap per load.
Rather than give diabetics (or caregivers for diabetics) units marked with mL’s, they try to make it easier for them by giving them syringes marked with units. It is easy if you’re using syringes marked for the strength of insulin you’re using – but if you’re not you need to convert.
1 unit of U-100 insulin = 1 “whole unit mark” on a U-100 syringe.
1 unit of U-40 insulin = 1 “whole unit mark” on a U-40 syringe.
1 unit of U-40 insulin = 2.5 “whole unit marks” on a U-100 syringe.
U-100 syringe with notes for U-40 insulin doses
There’s a nice printable conversion chart located here:
Conversion chart: http://www.felinediabetes.com/insulin-conversions.htm
Edited to add: Read more of my posts about feline diabetes
Life of the Lintee Bean 
Invaluable advice, which I hope I’ll never need! However, I shall file it away just in case. A friend of mine got her old boy into long-term remission usîng Elizabeth Hodgkins protocol, but she had real problems finding suitable syringes (she’s in Ireland) and ended up, I think, importing from the US. Axx
Hi, its 3:oo AM, my cat Phoebe was diagnosed last week with diabetes.
Im just now recovering well from a fall off the roof- so, perfect timing , couldnt have done this 2 weeks ago.
My Vet is waiting… to see if her raw meat & Hills diet straightens her sugar out. Tonight was bad, and a thought came to me, to give her a B12 shot.
I have a 8th grade education, I know nothing about diabetes, its skipped my collective knowlege bank.
I looked it up and the “thought” was right. I gave her almost 3 og a reg shot units- thats alot, I think, but she was going down. Shes resting now.
How much how often?
Thanks, August~
How much water should I be giving her? Her poop is so dry, when she can go. I have to “help” sometimes, Ive tried olive oil.
We are miserable.
My Vet (small town) didnt even suggest raw meats, I read it & went ahead with it, shes getting the Perscription Diet canned food too.
I dont know what else to give her, and cant buy anything here anyway (small town again).
Can you tell me another food to use? It costs $1.79 per can, and Ive taken my other cat off her dry food too.
I have 600 dollars a month, and I will start selling on ebay again .
I ordered an I-pet starter kit monitor.50 bucks !
help! Thanks…again. August~
Hi August,
First, I’d suggest you look at some of my other posts on feline diabetes:
https://meowmeowmom.wordpress.com/tag/diabetes/
In particular, this one:
https://meowmeowmom.wordpress.com/2008/08/04/feline-diabetes-beliefs/
It talks specifically about food options – including non-prescription canned foods like 9-Lives ground dinners.
Note that raw meat alone is NOT nutritionally complete, see:
https://meowmeowmom.wordpress.com/2008/12/04/raw-done-right/
You don’t need a special “pet monitor” – those made for human use work fine.
For more info, see:
http://www.felineoutreach.org/Education/DiabetesMellitus.html
Best of luck,
Lynette
Give her as much water as she wants! The all-wet diet should help with the stools – they SHOULD be rather dry, as long as she’s not straining in the litterbox, she’s most likely fine.
Lynette
THANK YOU THANK YOU THANK YOU! I even asked the pharmacist about the difference between U-40 and U-100 insulin and he didn’t know! he said 1 unit=1unit, but didn’t realize that the volume of liquid is different! You just helped me save so much money!!!!!!!!! God Bless You!!
Awesome charts. I’m actually studying on cross rating in the navy from an aircraft mechanic to a hospital corpsman. I’m still a little unsure however about measuring cc on a syringe. If a diagram on that could be posted that would be awesome.
Thanks.
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