How and when to change your insulin dose

You need to learn how to change insulin doses on your own.

Insulin doses need to be raised or lowered:

• Throughout life as you grow
• For different activities
• For foods that may affect your blood sugar differently
• When you are sick

The information on the following pages may be hard to learn. Learning to change insulin doses can take time. It is important to learn this because changing insulin doses at home when needed and between diabetes appointments will help to control your blood sugar.

It is better to prevent high blood sugars than to chase them with extra insulin at the time of the high. It is better to prevent low blood sugars than to chase them with extra quick-acting carbohydrate.

Your certified diabetes educator (CDE) will teach you how to change your insulin doses to prevent high or low blood sugar. We will help you by phone or email for several months after you find out you have diabetes. After you learn to change insulin doses without our help, we are still here to help you when you need.

Before you learn how to change insulin doses, you will need to:

Know the action of both your long-acting and rapid-acting insulins:

• When insulin starts to work
• When insulin peaks
• When insulin is done working

Learning about when insulin works will help you know which insulin dose to change.

Know your target range for blood sugar.

• Blood sugar target range before meals: 70 to 150
• Blood sugar target range at bedtime and during the night: 90 to 150

Try to get half of your blood sugars in the target range. It is okay to have 2 to 4 low blood sugars in a week.

The rest of your blood sugars may be higher than the target range.

Know what causes high blood sugar:

• Eating too much carbohydrate or too much quick-acting carbohydrate
• Not enough activity
• Stress
• Insulin may need to be increased
• Forgetting to take insulin
• Illness or infections
• Injury or surgery

Know what causes low blood sugar:

• Taking too much insulin
• Not eating enough carbohydrate after taking insulin
• Getting more activity than normal
• Drinking alcohol

Know that when you check your blood sugar, the number tells us how well your last dose of insulin worked.

For example, meal rapid-acting insulin peaks in 1 to 2 hours and lasts 3 to 4 hours. Your blood sugar taken 2 hours after the meal tells us how well the peak of the insulin covered the peak of the blood sugar after you ate. Your blood sugar taken before the next meal tells us how well the insulin worked during the time your carbohydrate was breaking down.

Know to look down each column on the blood sugar log to see if there is a pattern of high blood sugar or a pattern of low blood sugar.

There are 6 columns:

• Before breakfast
• 2 hours after breakfast
• Before lunch
• 2 to 3 hours after lunch
• Before supper
• 2 to 3 hours after supper before the bedtime snack

Know a pattern of high blood sugar is when blood sugars are over the target range of 150 for 3 days in a row when you look down the column.

To bring high blood sugars down and break the pattern of high blood sugar, your insulin dose that affects that column needs to increase.

Know a pattern of low blood sugar is when blood sugars are lower than the target range of 70 or 80 (based on your age) for 1 to 2 days in a row when you look down the column.

To bring low blood sugars up and break the pattern of low blood sugar, your insulin dose that affects that column needs to decrease. Change your insulin dose if you cannot find another reason for the high or low blood sugars.

Know that when you increase or decrease a dose of insulin, your current insulin dose will change by 10 percent.

Let’s practice changing insulin doses

When you practice, it will help you understand which insulin dose was changed and why it was changed.

Practice 1

Reference the breakfast column on Dec. 2, 3, and 4.

• These 3 days in a row that show a pattern of high blood sugars over the target blood sugar range of 150.
• This means the last insulin dose taken, the long-acting insulin from the night before, needs to be increased (go up) by 10 percent.

Next, look at the long-acting insulin dose column at bedtime, on Dec. 4.

• You will see the long-acting insulin was increased from 18 units up to 20 units. This is a 10 percent change.

Practice 2

Reference the before bedtime column of blood sugars on Dec. 5, 6, and 7.

• These 3 days in a row show a pattern of high blood sugar over the target blood sugar range of 150.
• This means the last insulin dose taken, before supper, needs to be increased by 10 percent.

Next, look at the before supper insulin column for the next day, on Dec. 8.

• You will see the before supper insulin dose was increased from 5.5 units up to 6 units. This is a 10 percent change.

Practice 3

Reference the before lunch column of blood sugars on Dec. 11 and 12.

• These 2 days in a row show a pattern of low blood sugar less than the target range of 70 to 80 (based on age).
• This means the last insulin dose taken, before breakfast, needs to be decreased by 10 percent.

Next, reference the before breakfast insulin dose for the next day, on Dec. 13.

• The before breakfast insulin dose is decreased from 7 units down to 6 units. This is a 10 percent change.