The odds of remission I've gleaned from studies over the years (with a low carb canned diet and home monitoring) are 80+% for Lantus and Levemir, 40-60% for Prozinc/PZI, and approximately 20-25% for Vetsulin/Novolin (with Vetsulin performing slightly better than Novolin in cats). 20-25% is also the estimated number of cats that go into remission from diet change alone, so it does make me wonder if the majority of cats that reach remission on these insulins would have gone into remission regardless of the insulin used. If you do start with either of those insulins (and I wouldn't recommend it), I would not use them for any longer than 4 weeks before switching if they aren't working well.
Lantus is pricy in the US, but there are affordable ways to get it! Many of us order from
Mark's Marine Pharmacy in Canada to get our insulin at a fraction of the price it costs in the US. All you need is a script from your vet. Many vets and owners choose the vetsulin/novolin route because it appears cheaper, but it's actually not! A five pack of Lantus pens (think of them as 5 mini vials), costs about $170 after shipping. Each pen will last you 2-3 months or more with good handling, so that $170 will last you the whole year (less than $15 a month). A vial of Novolin will cost you minimally $26 a vial, but the vial will only last a month. When you take into account that Lantus will give you much better control over your cats blood sugar and is far safer, and the Novolin will likely give you poor control and require more intense monitoring to safely administer, the Lantus is the much better deal! Not to mention that for most cats on Lantus, it's a one-time cost if they go into remission, and cats are unlikely to reach remission on Vetsulin or Novolin.
If you need to get your vet on board with your choice, here's a link to the
American Animal Hospital Association guidelines that state Lantus (glargine) and Prozinc are the recommended insulins for cats, and lente (vetsulin) insulins should not be used. I've also attached an article on Lantus below that discusses administering and remission rates for the insulin. I would print both of these out to bring to your vet!
