Driving and insulin 

By law, if you are prescribed insulin, you must tell:

This is because of the risk of having a hypo while you are driving. If you have a hypo, this could cause an accident as you will be slower to react to things while driving, or could pass out. If you don’t tell the DVLA, you could be fined up to £1000, and you could also be prosecuted if you have an accident.

If you only take tablets to manage your diabetes, check with your doctor or diabetes nurse whether you need to tell these organisations.

You should also tell these organisations about any changes in your diabetes or treatment. This includes any complications which might affect your ability to drive safely. For example, if you have had a severe hypo where you needed help from another person.

You can read more on the GOV.UK and nidirect websites.

How to drive safely if you take insulin

Check your blood sugar level less than 2 hours before the start of your journey, and every two hours during the journey.

If your blood sugar level is 5mmol/l or less, you should have some carbohydrate before driving. Some people find it helpful to remember this as ‘five to drive’.

If your blood sugar level is less than 4mmol/l before or during driving, do not drive. This is hypoglycaemia, and you should follow these steps.

  • Stop the vehicle.
  • Switch off the engine, remove the keys from the ignition and move from the driver’s seat.
  • Take some fast acting carbohydrate such as glucose tablets or jelly babies.
  • Wait 10 minutes, then check your blood sugar level again. If it’s higher than 4, take some longer acting starchy carbohydrate. If you take pancreatic enzymes, don’t forget to take these with it.
  • Do not start driving until 45 minutes after your blood sugar level has returned to above 5mmol/l.
  • If you use a flash glucose or continuous glucose monitor and the reading is 4mmol/l or below, you must stop driving and confirm your glucose test reading with a finger prick test.

Always take your blood sugar monitor and some fast acting carbohydrate with you when you drive. It’s a good idea to keep an emergency supply of carbohydrate in your car.

Ask your doctor or diabetes nurse if you have any questions about driving.

Physical activity if you take insulin

Physical activity can help you feel better and cope with your cancer treatment.  Physical activity may affect your blood sugar levels, making you more likely to have a hypo. If you take insulin, speak to your diabetes team about managing your blood sugar levels while exercising.

If you start to do more physical activity, you may need to change the amount of carbohydrate and/or insulin you have. Your diabetes team can help you with this.

It’s a good idea to monitor your blood sugar levels before, during and after exercise. This can help you understand how exercise affects your blood sugar levels. Try keeping a record of your blood sugar levels while you are exercising, to spot any trends. If your blood sugar levels drop during or after exercise, then always keep hypo treatments with you.

You may be more likely to have a hypo during exercise, just afterwards and 6-8 hours later. Your blood sugar levels can keep dropping even the day after physical activity.

Eating out if you take insulin 

Eating out can be a chance to see friends and family and do something you enjoy. You can still eat out if you have diabetes, but you may need to change the timing or amount of insulin you take. Speak to your diabetes nurse about this.

If you have larger portions or more fatty foods when you eat out, remember that you may need more pancreatic enzymes with this food. If you take longer to eat your meal or have several courses, you may also need to take more enzymes, and spread them out through the meal.

Alcohol and insulin

Talk to your diabetes team about whether you can have a small amount of alcohol, and how much they would suggest as the limit.

Drinking and hypos

Drinking alcohol makes hypoglycaemia more likely. And if you have had too much alcohol, you may not recognise or treat a hypo properly.

Make sure that you tell the people you are drinking with that you have diabetes. Sometimes people mistake the signs of a hypo for being drunk. You might also want to tell them how to treat a hypo.

Things to be aware of when drinking alcohol

  • Never drink alcohol on an empty stomach or after exercise. Always have some starchy carbohydrate when drinking alcohol.
  • Always carry identification with you, as well as a hypo treatment and your pancreatic enzymes when you are out.
  • Always have a starchy carbohydrate snack, such as cereal or toast, before going to bed if you have been drinking alcohol. Don’t forget to take your pancreatic enzymes with it.

Read more about things to be aware of when drinking alcohol on the Diabetes UK website.

Monitoring your diabetes

If you have pancreatic cancer and type 3c diabetes, it can be hard to deal with symptoms and to work out what is causing them. It is a good idea to keep a record so that you and your diabetes team can look back and spot any patterns.

Here are some ideas about what to record:

  • what you have had to eat and drink
  • how much insulin or other medicines you have taken
  • how many pancreatic enzymes you have taken
  • your blood sugar level readings
  • how active you have been
  • any symptoms you have had, such as diarrhoea (runny poo), bloating, tiredness, high temperature, dizziness or pain.

We have a diary that you could use to monitor your diabetes.

How can illness affect blood sugar levels?

Illness and infections can raise your blood sugar levels. Even if you are not eating, your blood sugar level can still rise when you are ill. This is because the body releases sugar into the blood as it fights infections.

If you take tablets for your diabetes, the tablets may not work properly if you are sick or have diarrhoea. This can cause a rise in blood sugar levels.

What to do if you are ill

Your diabetes nurse may have told you how to manage your diabetes if you are ill, for example if you have flu. Follow their guidance.

If you are unwell and you have not been given guidance, speak to your diabetes nurse. They will be able to give you advice for your specific situation. If you can’t speak to your diabetes nurse, contact your GP or medical team.

If you are being sick for more than half a day, are not improving, or are unsure what to do, get urgent medical advice from your medical team or NHS 111.

Diabetic ketoacidosis (DKA) and hyperosmolar hyperglycaemic state (HHS)

If you have diabetes, an illness or infection can sometimes cause conditions called diabetic ketoacidosis (DKA) or hyperosmolar hyperglycaemic state (HHS). These happen when blood sugar levels become very high.

If you are unwell, speak to your diabetes team.

Both conditions have similar symptoms, which can include:

  • high blood sugar levels
  • feeling very thirsty
  • needing to pee more often
  • feeling tired and sleepy
  • confusion
  • blurred vision
  • stomach pain
  • feeling or being sick
  • sweet or fruity-smelling breath (like nail varnish or pear drop sweets)
  • passing out.

DKA and HHS are both serious conditions that need treating urgently. Go to A&E immediately if you think you have DKA or HHS. Tell them you have diabetes.

Find out more about DKA and HHS from Diabetes UK or ask your diabetes nurse for more information.

Questions about diabetes?

If you have any questions about managing diabetes and its affects on your life, speak to your diabetes team.

You can also speak to our specialist nurses on our free Support Line with any questions.

Speak to our nurses
Pancreatic Cancer Nurse Jeni Jones

Updated June 2023

Review date June 2026