Hypoglycaemia

The risk of hypoglycaemia is the main hazard when driving. This may endanger your own life as well as that of other road users. There is a risk of hypoglycaemia ('hypo') if your diabetes is treated with insulin or with the following diabetes medications:

Any tablet from the sulphonylurea or prandial glucose regulator groups increase the risk of hypoglycaemia.

Any other diabetes treatment, including non-insulin injections, may not cause hypoglycaemia when taken on its own, but when used in combination with any of the tablets listed below then the risk of hypoglycaemia is increased.

If you are not sure if your medication can cause a hypo, discuss this with your diabetes healthcare team. It is an offence to drive whilst unfit through drugs; the law does not distinguish between 'illegal' drugs and prescribed medication and having a hypo while you are in charge of a motor vehicle can be fatal, not only for you, but for others as well.

You should always carry some form of glucose (such as a sugary non-diet drink or glucose tablets) with you in your pocket or handbag. Also keep glucose tablets and biscuits, fruit or sandwiches in the car. You should also check your levels before you drive and whenever you take a break. If you have a passenger with you, it is a good idea to tell them you have diabetes and what to do if you need help dealing with a hypo.

Many of the accidents caused by hypoglycaemia are because drivers continue to drive even though they are experiencing warning signs of hypoglycaemia. The symptoms of hypoglycaemia may include feeling hungry, sweating, shakiness, palpitations, feeling faint, dizziness, nausea or a headache. Sometimes you may notice blurred vision or tingling of the lips.

If you experience warning signs of hypoglycaemia while driving and think you are having a hypo:

• Stop driving as soon as it is safe to do so. Do not attempt to start again until the symptoms have disappeared. (The DVLA advises that you wait 45 minutes after the blood glucose returns to normal).
• Take glucose tablets or some other form of fast acting carbohydrate immediately.
• Make it clear that you are no longer in charge of the car by leaving the driving seat, stepping out of the car (if safe to do so) and by removing the ignition key.

You must inform the DVLA if:

• You have more than one episode of severe hypoglycaemia within 12 months, or if you or your carer feels you are at high risk of developing disabling hypoglycaemia. 'Severe hypoglycaemia' is now defined as requiring the assistance of another person.
• You develop impaired awareness of hypoglycaemia (difficulty in recognising the warning symptoms of low blood glucose levels). Your GP or diabetes consultant will be able to assess this.
• You experience disabling hypoglycaemia while driving (defined as requiring the assistance of another person).
• An existing medical condition gets worse or you develop any other condition that may affect your driving safely.

Remember – you can help avoid hypoglycaemia by:

• never driving for more than two hours without testing your blood glucose and stopping for a snack if necessary 
• not delaying or missing a meal or snack
• checking your blood glucose before and during a journey.

If you have lost or have poor warning symptoms of impending hypoglycaemia or have frequent hypos, you should probably not be driving because of the risk to yourself and other road users. You should discuss this with your diabetes healthcare team. You should also notify the DVLA/DVA. If your diabetes healthcare team advise you not to drive or to notify the DVLA/DVA, you must do so. If you fail to notify the DVLA/DVA and continue to drive, your doctor has an obligation to give you a final warning and then to notify the DVLA/DVA on your behalf.

Reviewed May 2012