We would like to know why my wife’s blood glucose level spike after taking her insulin? It will spike as much as 200 mg/dl [11.1 mmol/L], then five to six hours later, it drops to all most nothing which makes it very hard to manage her diabetes. She is taking five units of NPH and uses a sliding scale for the Regular.

Could it be that the blood sugars would spike anyway? For instance, are you giving the insulin after meals, a time when blood sugars would normally rise? The injection of insulin does not normally cause blood sugars to go up. I would suggest you consider trying one of the insulin analogs instead of using Regular insulin. These insulins have an immediate action and last only three hours. This makes them safer to use and leads to less distant low blood sugars. Your total insulin doses appears to be rather small. Once a day NPH is not much and sliding scale regular is not very efficient. I tend to recommend using rapid-acting insulin with meals with the goal of preventing the sugar from being high in the first place, rather than waiting till it already gets high. You end up using more insulin that way as it always takes more insulin to bring the blood sugar down once it is elevated. I would recommend you speak with your physician about changing your regimen.

JTL