The medical industry has developed standard formulas for calculating insulin dosages for newly diagnosed diabetic patients. These initial calculations are then adjusted to meet each individual's needs. Because of the heightened risk of severely high or low blood sugars during this initial stage, calculation of dosage should never be attempted without the assistance of a doctor, and is usually done in a hospital setting.

Considerations

The amount and frequency of insulin dosages depends on the diabetes a person is diagnosed with: type 1 (the pancreas produces no insulin) or type 2 (the pancreas produces some, but not enough, insulin). A person's age and weight are also factored in. Typically, a type 1 diabetic will need more insulin, administered more frequently, than a type 2 diabetic.

Types

Generally speaking, there are two types of insulin: long-acting, or basal, insulin that processes glucose needed to perform "background" tasks throughout the day and night, and short-acting, or bolus, insulin that processes carbohydrates eaten at meals and snacks. A type 1 diabetic needs both types of insulin (unless an insulin pump, which delivers tiny bursts of short-acting insulin all day, is used). A type 2 diabetic may have enough natural insulin to cover basal tasks but may need short-acting insulin injections to cover any carbohydrates eaten.

Calculating Total Insulin Needed

The initial insulin dosage is 0.4 units/kg/day total. Half of this will be delivered as basal and half as bolus. Blood sugar levels must be very closely monitored during this initial stage to determine whether this amount is too high or too low. Low blood sugar (anything below 70 mg/dL) must be treated with fast-acting sugar, like juice or raisins; high blood sugar (any before-meal reading above 120 mg/dL) must be treated with additional bolus insulin.

Calculating Basal Dosages

In consultation with your doctor, determine which type of long-acting insulin you will use and how frequently it must be injected. For example, the long-acting insulin glargine (brand-named Lantus or Levemir) lasts upwards of 24 hours and is generally injected twice a day (half in the morning, half at night). The intermediate-acting insulin NPH lasts upwards of 8 to 12 hours and is generally injected three times a day. Your doctor may recommend combining NPH and Lantus/Levemir for tighter control as you move forward. Depending on the number of daily injections, take half of the total insulin dosage you calculated above and then divide that number by the number of daily injections to arrive at your expected initial dosage.

Calculating Bolus Dosages

Initial insulin dosages for covering mealtime carbohydrates are generally 1 unit of short-acting insulin for every 15 grams of carbohydrate. Testing blood sugar one hour after eating will reveal whether this dosage needs to be increased.

Source:

Clinical Diabetes: Insulin Care Strategies for Primary Care Providers

Maine Health System: Floor Management Guidelines for Diabetes