How do I adjust insulin doses?
Information for patients
To reduce fluctuations in blood glucose, aim to keep carbohydrate portions similar on a day to day basis.
These instructions are guidelines. If you are unsure of how to adjust your insulin or if your blood glucose continues to remain out of target, do not hesitate to contact your diabetes nurse.
Adjusting insulin doses
Note: Do not adjust your insulin on the basis of one blood glucose reading, wait and see if there is a pattern (usually 2 to 3 days)
How your insulin works
Morning insulin
Administered before breakfast. Works throughout the day up to your evening meal.
Evening insulin
Administered before evening meal. Works throughout the the evening and overnight.
Why are my blood glucose levels sometimes high
A temporary high blood glucose level from time to time is impossible to avoid in everyday life.
Reasons include:
- Infection
- Problem with injection technique
- Certain food or drink (high sugar or high carbohydrate)
- Stress
- Steroid therapy
- Missed insulin or insufficient insulin
General guidelines about insulin adjustment for high blood glucose
Consider increasing your insulin dose by 2 units or 10% of insulin dose every 3 to 4 days.
An example: 10% of 30 units would be 3 units, so increase dose to 33 units. The dose of insulin given before the higher readings should be increased.
If blood glucose level is:
- high before lunch and before evening meal, increase morning
insulin dose. - high before bed and before breakfast, increase evening insulin dose.
If your blood glucose is high then you require more insulin.
Why are my blood glucose levels sometimes low?
- Missed or delayed meals
- Not enough or no carbohydrates (for example, rice, cereal, pasta, potatoes)
- Too much insulin
- Increased exercise, unexpected exercise
- Hot weather
- Problem with injection technique
- Alcohol
General guidelines about insulin adjustment for low blood guidelines
If you know the reason for the low blood glucose level then take action to prevent it from happening again (for example, a missed meal).
Consider decreasing your insulin dose by 2 units or 10% of insulin every 3 to 4 days.
An example: 10% of 30 units would be 3 units so to decrease dose to 27 units. The dose of insulin given before the lower readings should be reduced.
If blood glucose level is:
- low before lunch and before evening meal, reduce morning insulin dose
- low before bed and before breakfast, reduce evening insulin dose.
If your blood glucose is low then you require less insulin.
Hypoglycaemia
If you have an unexplained ‘hypo’ (blood glucose below 4mmol/ls) then reduce your insulin dose by 20%.
An example: 20% of 10 units of insulin would be 2 units, so reduce dose to 8 units. The dose of insulin given before the hypo should be reduced.
Note: Do not adjust your insulin on the basis of one blood glucose reading, wait and see if there is a pattern (usually 3 to 4 days).
Ideally blood glucose levels should be between 4 to 7mmol/ls before meals (your personal targets may be higher than this).
Why are my blood glucose level sometimes high?
A temporary high blood glucose level from time to time is impossible to avoid in everyday life.
Reasons include:
- Infection
- Problem with injection technique
- Certain food or drink (high sugar or high carbohydrate)
- Stress
- Steroid therapy
- Missed insulin or insufficient insulin
General guidelines about insulin adjustment for high blood glucose
If the pattern of blood glucose level is still high before mealtime for a period of 3 days consider increasing your insulin dose by 2 units or 10% every 4 days.
An example: 10% of 30 units would be 3 units, so increase dose to 33 units. The dose of insulin given before the higher readings should be increased.
If given in the morning, increase the dose if:
- blood glucose level is high before lunch and evening meal.
If given in the evening, increase the dose if:
- blood glucose level is high before breakfast.
If your blood glucose is high then you require more insulin.
Why are my blood glucose levels sometimes low?
- Missed or delayed meals
- Not enough or no carbohydrates (for example, rice, cereal, pasta, potatoes)
- Too much insulin
- Increased exercise, unexpected exercise
- Hot weather
- Problem with injection technique
- Alcohol
General guidelines about insulin adjustment for low blood glucose
If you know the reason for the low blood glucose level, take action to prevent it from happening again (for example, a missed meal).
If you have an unexplained ‘hypo’ (blood glucose below 4mmol/ls) then reduce your insulin dose by 20%.
An example: 20% of 10 units of insulin would be 2 units, so reduce dose to 8 units. The dose of insulin given before the hypo should be reduced.
If given in the morning, reduce the dose if:
- blood glucose level is low before lunch and evening meal.
If given in the evening, reduce the dose if:
- blood glucose level is low before breakfast.
If your blood glucose is low then you require less insulin.
Note: Do not adjust your insulin on the basis of one blood glucose reading, wait and see if there is a pattern (usually 3 to 4 days).
Ideally blood glucose levels should be between 4 to 7mmol/ls before meals (your personal targets may be higher than this).
Why are my blood glucose levels sometimes high
A temporary high blood glucose level from time to time is impossible to avoid in everyday life.
Reasons include:
- Infection
- Problem with injection technique
- Certain food or drink (high sugar or high carbohydrate)
- Stress
- Steroid therapy
- Missed insulin or insufficient insulin.
General guidelines about insulin adjustments for high blood glucose
Every 3 to 4 days review your glucose results.
If your blood glucose readings before breakfast are above target range and you have experienced no hypoglycaemia (blood glucose less than 4mmol/l), increase your insulin by 2 units or 10%.
An example: 10% of 30 units would be 3 units, so increase dose to 33 units.
Continue increasing your dose until your blood glucose before breakfast is within your target range.
If your blood glucose is high then you require more insulin.
Why are my blood glucose levels sometimes low?
- Missed or delayed meals
- Not enough or no carbohydrates (for example, rice, cereal, pasta, potatoes)
- Too much insulin
- Increased exercise, unexpected exercise
- Hot weather
- Problem with injection technique
- Alcohol
General guidelines about insulin adjustment for low blood glucose
Every 3 to 4 days review your glucose results.
If your blood glucose readings before breakfast are below target range reduce your insulin by 2 units or 10%.
If you know the reason for the low blood glucose level, take action to prevent it from happening again (for example, a missed meal).
If you have an unexplained ‘hypo’ (blood glucose below 4mmol/ls) then reduce your insulin dose by 20%.
An example: 20% of 10 units of insulin would be 2 units, so reduce dose to 8 units. The dose of insulin given before the hypo should be reduced.
If your blood glucose is low then you require less insulin.
