Hi and welcome to you and your kitty.
I don't know anything about Vetsulin causing such a reaction but hopefully other members who read your thread may have suggestions or information for you. Have you let your vet know?
With regard to Lantus, maybe we can help you find an affordable supply of Lantus. If you move quickly you might be able to get some that's currently on offer in the FDMB Supply Closet. Look at this link:
http://www.felinediabetes.com/FDMB/...-exp-i-found-a-little-more-35-per-pen.153819/
Also a lot of people here get a written prescription from their vets and order their Lantus from Marks Marine Pharmacy in Canada (where it is MUCH cheaper than in the US). More info on this link:
http://www.felinediabetes.com/FDMB/...canadian-pharmacies.49608/page-2#post-1344374
IMPORTANT NOTE:
If you do switch to Lantus you will need to use U100 syringes because the concentration is different to Vetsulin (i.e. DO NOT use Vetsulin syringes with Lantus insulin). The best syringes to get are 0.3ml U100 syringes with half-unit markings (easier to make fine dose adjustments with these ones).
Mogs
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