Sliding scale insulin therapy is a method of determining the appropriate insulin dose based on pre-defined blood glucose ranges. It involves a progressive increase in the pre-meal or nighttime insulin dose, depending on the individuals blood glucose levels. This approach is designed to approximate daily insulin requirements and is more precise than fixed-dose insulin, as it takes into account the fluctuating blood glucose levels in individuals with diabetes.

The general principles of sliding scale therapy include pre-setting the amount of carbohydrate to be eaten at each meal, keeping the basal (background) insulin dose constant, and adjusting the bolus insulin based on the blood sugar level before the meal or at bedtime. Sliding scale regimens may include a bedtime high blood sugar correction. However, there are some disadvantages to this method, such as its inability to accommodate changes in insulin needs related to snacks, stress, and activity, as well as the requirement to count carbohydrates. Additionally, sliding scales are less effective in covering a pre-meal high blood sugar, as the high blood glucose correction and food bolus cannot be split.

While sliding scale insulin therapy was developed several decades ago as a guide to insulin dosage, it is now less commonly used, with many healthcare professionals advising against its use. Instead, alternative methods of insulin administration, such as conventional insulin therapy, are recommended by the American Diabetes Association (ADA) .

In summary, sliding scale insulin therapy is a method of determining insulin dosage based on blood glucose levels, but it has limitations and is now less commonly used in favor of more flexible and effective insulin administration methods.