> We started at 3 units of Lantus SoloStar insulin. We have gradually
> moved up to 5 units, he has been to the vet for a glucose curve once.
Lantus is a great insulin to work with, and kudos to your vet for choosing it for you; many vets recommend older insulins which aren't as good as Lantus. Unfortunately, it also appears that your vet is treating Lantus as if it were one of the older insulins; it isn't, and it has to be handled differently. You really should re-start the Lantus at 1 unit twice a day, and then very gradually work your way up from there. There are a lot of folks here using Lantus (I'm not one of them), and they can help you with recommendations on dosing.
> She is open to allowing use to test at home but we have not had much
> luck getting enough blood for his ear to get a reading.
Are you using a regular human glucometer, or a pricy one the vet sold you? The vet glucometers usually need more blood than the human ones; they're also way more expensive, and the strips are harder to get as well as being more expensive. A human glucometer is just as accurate, less expensive to buy, and the strips are easier and less expensive to get.
On testing: are you warming the ear beforehand? A warm ear is one of the keys in getting blood samples. A lot of folks use a rice sock to warm the ear beforehand, or rub the ear between our fingers to encourage circulation. You can also 'milk' the ear for blood after pricking. Finally, if your cat is a head-shaker, you can gather the blood on your fingernail before it's shaken off, and test from there. Other than that, check out Hometesting Links and Tips here
http://felinediabetes.com/FDMB/viewtopic.php?f=14&t=287.
> However he still seems to be drinking alot of water and urinating a
> lot as well.
The drinking and urinating will clear up as the diabetes comes under control.
> Unforunately, due to his neuropathy and I am assuming the diabetes he
> is not always making it to the litter box and ends up peeing on the carpet.
Do you know that it's neuropathy? A lot of cats with unregulated / under-regulated diabetes develop urinary tract infections, and urinating in inappropriate places is one of the signs of a possible UTI.
> Needless to say the neuropathy has not improved much either. [...] I spoke
> to my vet about using methly B12. She was open to the idea but concerned
> with the additional chemicals that could be present with human supplements.
> She suggested that we try using an injectable B12. He has had two doses of
> the B-12 as recommend in a once a week dose. I know I should be patient but
> I am concerned that the injectable B-12 will not be as effective as the methly
> B-12.
There are two types of B-12. The type that's most used is cyanocobalamin; the not-much-used-at-all type if methylcobalamin.
*If* your vet is giving injections of methylcobalamin, then that's more effective than oral methylcobalamin. If your vet is giving injections of cyanocobalamin, that is probably less effective than oral methylcobalamin. (In all probability, your cat is getting injections of cyanocobalamin.)
You *can* start your cat on oral methylcobalamin, which you can find online or at some health food or vitamin stores. Some brands contain sugar and others don't, but most of us don't worry excessively about that. Nor, for the most part, the other ingredients. (I tend to stay away from those with mannitol, sorbitol, and xylitol, but my Gwyn has a *lot* of problems.)
Please note that the cause of diabetic neuropathy is diabetes, and the only real cure for it is to get the diabetes under control. If the diabetes isn't controlled, then the methyl-B12 can help slow the progression. Once the diabetes is under control, the cat's neuropathy will start to heal on it's own, and the methyl-B12 can help speed the healing. But the methyl-B12 won't work on it's own; you need to control the blood sugar levels.
Has anyone talked to you about testing for ketones? Ketones are a not-common side effect of unregulated or under-regulated diabetes. While they're not common, they *are* (unfortunately) one of those problems that, if they do occur, can turn Very Bad (quickly. Low levels of ketones may be treatable at home; high levels of ketones may require hospitalisation at a 24-hour care facility. You can read more about ketones here
http://petdiabetes.wikia.com/wiki/Ketones.
To test for ketones, stop by the diabetes section of your local pharmacy and pick up ketostix. You stick them in fresh urine and, if ketones are present, the strip on the stick changes color. (Larger color changes indicate the presence of more ketones.) IIRC, it's about $15-20 for a bottle of 90 sticks.
Also, does your cat have any other health issues going on at the moment, besides the diabetes and the urinating and the neuropathy? I'm asking because a lot of times a cat will be borderline diabetic and something happens -- inflammation, infection, pain, something -- and the blood sugar levels rise because of the problem and the cat becomes a full-blown diabetic. If you can treat the cause of the increased blood sugar levels, you increase the chance of getting your cat into remission (that's where your cat doesn't need insulin). So if there were any other health issues present, even something comparatively minor like tartar on the teeth, I'd suggest getting those treated sooner than later.
The two other things you're going to hear about from a lot of folks here is to switch to a low-carb food. Changing over to a low-carb canned (or raw) food will definitely lower BG levels, and lower the amount of insulin your cat needs. A low-carb diet is one of the key components in getting any cat into remission. However, please do not change diets until you're fairly comfortable home-testing blood sugar levels; with the levels of insulin you're giving at the moment, changing diet without home-testing could have Bad Consequences.
If you have any questions, feel free to ask; we're all here to help each other.