I'm sorry but there is no generic that works the way that Actos and Avandia do, or that will provide their level of glycemic control. The best method to control costs is to increase the insulin dosage and drop the glitazone altogether. That along with careful control of diet and exercise usually takes care of both pre- and post-meal glucose levels. Your endocrinologist will need to experiment, but increasing the basal insulin and decreasing the generic oral that you take may be what works best. I've got some patients just on Lantus who are having better A1Cs that they did for years of oral meds plus insulin.
Wow, I don't really like your doctor's plan. Lantus is a basal insulin that lasts up to 24 hours. It isn't something you want to give PRN but on a set schedule. Many patients take nothing but Lantus. Others require metformin as well.
The alpha-glucosidase inhibitors prevent the digestion of carbohydrates. They are taken before each meal. They are most useful for reducing postprandial glucose since they prevent the conversion of carbohydrate to glucose. With less glucose available for absorption, the glucose available to go into the blood is lower. Since the carbohydrates aren't digested, they remain in the colon where the intestinal bacteria work on them and can cause gas, bloating, abdominal pain, flatulence and diarrhea. This is the number one reason people stop taking the drug. Depending on the diet, they have the potential to lower A1C from about 0.5 to 1.0%. They are contraindicated in any kind of intestinal disorder (irritable bowel syndrome, Crohn's, etc.) or liver disease. Generics are available but they aren't a lot less expensive than the brand names (Precose, Glyset).
The amino acid derivative nateglinide (Starlix) does not have a generic. It works by helping your pancreas release more insulin and is taken beofre each meal. It is not as effective as glyburide and some of the other oral agents. I've never had a patient on this, so have no pointers to pass along.
The dipeptidyl peptidase-4 inhibitor sitagliptin (Januvia) also works by regulating insulin levels. It is not approved for use with insulin.
Repaglinide (Prandin) is taken before each meal to increase secretion of insulin. It binds to the beta cells of the pancreas and has very short duration.
The last part of your feedback comments were cut off, so I can't remember exactly what types of drugs you knew about and which ones you don't. Since you are taking metformin and glimepiride, I assume you understand how they work.
There is no generic for Prandin yet but it is marginally cheaper to use than Actos.
I think I did read your original question clearly. You stated that your doctor advised you to bump up your Lantus PRN when you stopped Novolog. PRN means to increase the dose on an "as needed basis", just as you only take a Tylenol PRN when you have a headache. Lantus is not prescribed PRN. As a basal insulin, the same dose is taken daily.
As for whether it would be good to use, it wouldn't be my first choice, but it is a possibility. I'd titrate the Lantus upward unless you started to get hypoglycemic episodes, then lower it just to the point where you didn't. That should be all you need to keep your glucose under control without adding another medication (with its side effects) to the mix.