Calculating insulin dosage involves estimating the total daily dose (TDD) and then distributing it between basal and bolus insulin based on individual needs. Here's a breakdown of how to approach insulin calculation, according to the provided reference.
Estimating Total Daily Dose (TDD)
A common starting point for estimating TDD is based on body weight. According to the "general rule of thumb," the calculation is as follows:
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TDD = Weight in pounds / 4
Example: If a person weighs 160 pounds:
- TDD = 160 / 4 = 40 units of insulin per day
Basal vs. Bolus Insulin
If a patient requires both basal (long-acting) and prandial (mealtime, rapid-acting) insulin, the TDD is typically split evenly:
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50% Basal Insulin: This covers the body's background insulin needs, usually administered once or twice daily.
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50% Bolus Insulin: This covers carbohydrate intake at meals and is administered before eating.
Using the example of a TDD of 40 units:
- Basal Insulin = 40 units * 0.50 = 20 units
- Bolus Insulin = 40 units * 0.50 = 20 units
This 20 units of bolus insulin is then further divided across the meals of the day, based on carbohydrate content and individual insulin sensitivity. This often requires working with a healthcare professional or diabetes educator.
Important Considerations: These calculations are general guidelines only and must be individualized by a healthcare provider. Factors such as insulin sensitivity, activity level, kidney function, and individual metabolic needs will affect the final dosage.
