HealthInfo Canterbury
Managing insulin when you are sick
Te whakahaere i te taiaki huka mēnā e māuiui ana
Important
See your doctor urgently if:
- you're vomiting a lot or constantly
- you can't keep your blood glucose (sugar) levels above 4 mmol/l
- your blood glucose levels stay high
- you have type 1 diabetes and your blood glucose levels stay above 15 mmol/l after two extra doses of rapid-acting insulin (if you've been prescribed it) or if ketones are increasing or stay high
- you get worse or develop new symptoms.
If you're ill, need surgery or go through a period of severe emotional stress, you may need to change your normal diabetes routine.
When you're unwell. your body releases hormones that increase your blood glucose levels. Managing diabetes to avoid developing high blood glucose levels is different when you're sick. You may need more insulin, even though you may not be eating as much as usual or even vomiting.
If you have type 1 diabetes, you also need to avoid developing diabetic ketoacidosis (which is often called DKA).
If you're unwell:
- avoid hypoglycaemia (low blood glucose)
- avoid becoming dehydrated
- make sure you still eat well
- follow the advice below to prevent DKA if you have type 1 diabetes
- know when to ask for help.
Guidelines for managing sick days
- Relieve your symptoms. Take paracetamol regularly to reduce your fever and relieve any headaches or other discomfort. Talk to your general practice team about other medications for any specific illness.
- Keep using insulin. You may need to adjust the dose, but don't stop your usual injections.
- Test your blood glucose every two hours. If your blood glucose levels are less than 4 mmol/l, test them every hour.
- Measure your ketones if your blood glucose is persistently above 15 mmol/l and you have type 1 diabetes and use a ketone meter.
- Drink enough fluid – about a glass every hour.
- For type 1 diabetes, if your blood glucose levels are below 15 mmol/l and you aren't eating, drink sweetened fluids such as soft drink, lemonade ice blocks, ordinary jelly or fruit juice. If your blood glucose levels are above 15 mmol/l, drink unsweetened fluids.
- For type 2 diabetes, if your blood glucose levels are below 8 mmol/l and you aren't eating, drink sweetened fluids such as soft drink, lemonade ice blocks, ordinary jelly or fruit juice. If your blood glucose levels are above 8 mmol/l, drink unsweetened fluids.
- Keep good records – write down the results when you test your blood glucose.
- Avoid strenuous exercise, especially if testing shows ketones are present.
Surgery and fasting
If you have to fast before having surgery or a medical procedure, make sure you have guidelines for adjusting your insulin beforehand. Speak to your general practice team about this.
Replacing fluid
You can take rehydration solutions, such as Gastrolyte to replace fluid and electrolytes lost through diarrhoea or dehydration. But rehydration solutions have relatively low concentrations of carbohydrates so you may need extra carbohydrates.
Take care with sweetened fluids if you get diarrhoea. You may have to dilute them up to five times so you can absorb them well.
Written by nursing staff at the Diabetes Centre, Christchurch. Adapted by HealthInfo clinical advisers. Last reviewed November 2022.
Sources
See also:
Review key: HIDIA-21832
