Glibenclamide for diabetes

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Take glibenclamide with, or just after, your first main meal of the day (usually breakfast).

Remember to follow any advice you have been given about your diet and taking exercise.

Common side-effects include stomach upset and low blood sugar (hypoglycaemia). Make sure you know how to recognise the symptoms of low blood sugar. These include feeling shaky or anxious, sweating, looking pale, feeling hungry, having a feeling that your heart is pounding (palpitations), and feeling dizzy.

Type of medicineA sulfonylurea antidiabetic medicine
Used forType 2 diabetes mellitus
Available asTablets

Insulin is a hormone which is made naturally in your body, in the pancreas. It helps to control the levels of sugar (glucose) in your blood. If your body does not make enough insulin, or if it does not use the insulin it makes effectively, this results in the condition called sugar diabetes (diabetes mellitus).

People with diabetes need treatment to control the amount of sugar in their blood. This is because good control of blood sugar levels reduces the risk of complications later on. Some people can control the sugar in their blood by making changes to the food they eat but, for other people, medicines like glibenclamide are given alongside the changes in diet.

Glibenclamide works by increasing the amount of insulin that your pancreas produces. This helps to reduce the amount of sugar in your blood.

Some medicines are not suitable for people with certain conditions, and sometimes a medicine may only be used if extra care is taken. For these reasons, before you start taking glibenclamide it is important that your doctor knows:

  • If you are pregnant, trying for a baby or breast-feeding.
  • If you have any problems with the way your liver works, or with the way your kidneys work.
  • If you have been told you have porphyria or glucose 6-phosphate dehydrogenase (G6PD) deficiency. These are rare inherited disorders.
  • If you are taking any other medicines. This includes any medicines you are taking which are available to buy without a prescription, as well as herbal and complementary medicines.
  • If you have ever had an allergic reaction to a medicine.
  • Before you start the treatment, read the manufacturer's printed information leaflet from inside the pack. It will give you more information about glibenclamide tablets and will provide you with a full list of the side-effects which you may experience from taking them.
  • Take glibenclamide exactly as your doctor tells you to. The usual starting dose is 5 mg daily. It is prescribed as a single dose to be taken with, or immediately after, breakfast.
  • If you forget to take a dose at the usual time, take it with your next meal. If you do not remember until the following day, skip the missed dose. Do not take two doses on the same day to make up for a forgotten dose.
  • It is important that you keep your regular doctor's and clinic appointments. This is so that your progress can be monitored. You will need regular check-ups with an eye clinic and a foot clinic as well as with your doctor and diabetes clinic.
  • Your doctor may recommend that you test for sugar (glucose) in your blood regularly to check that your diabetes is being controlled. Your doctor or diabetes nurse will show you how to do this.
  • If you have been given advice by your doctor about changes to your diet, stopping smoking or taking regular exercise, it is important for you to follow the advice you have been given.
  • Make sure you know what it feels like if your blood sugar drops too low. This is known as hypoglycaemia, or a 'hypo'. The first signs of hypoglycaemia are feeling shaky or anxious, sweating, looking pale, feeling hungry, having a feeling that your heart is pounding (palpitations), and feeling dizzy. If this happens, eat something containing sugar, such as dextrose tablets, or sugary sweets or drinks (non-diet), and then follow this up with a snack such as a sandwich or a banana.
  • Low blood sugar (hypoglycaemia) can occur if you miss a meal, if you exercise more than usual, if you are ill, or if you drink alcohol.
  • Do not drink alcohol, as it can affect the control of your blood sugar. Ask your doctor if you need further advice about this.
  • If you are a driver you should take special care, as your ability to concentrate may be affected if your diabetes is not well controlled. You may be advised to check your blood sugar levels before you travel and to have a snack with you on long journeys.
  • Drivers in the UK may need to inform the Driver and Vehicle Licensing Agency (DVLA) if they experience an episode of severe hypoglycaemia or experience a 'hypo' whilst driving. Ask your doctor for advice. Drivers in other countries should contact the relevant vehicle licensing agency.
  • If you get unusually thirsty, pass urine more frequently than normal, or feel very tired, you should let your doctor know. These are signs that there is too much sugar in your blood and your treatment may need adjusting.
  • Check with your doctor before taking up any new physical exercise, as this will have an effect on your blood sugar levels and you may need to check your blood levels more regularly.
  • If you are due to have an operation or dental treatment, you should tell the person carrying out the treatment that you have diabetes and give them a list of the medicines you are taking.
  • If you buy any medicines, always check with a pharmacist that they are suitable for you to take.
  • Treatment for diabetes is usually lifelong. Continue to take the tablets unless you are advised otherwise by your doctor.

Along with their useful effects, most medicines can cause unwanted side-effects although not everyone experiences them. The table below contains some of the most common ones associated with glibenclamide. You will find a full list in the manufacturer's information leaflet supplied with your medicine. The unwanted effects often improve as your body adjusts to the new medicine, but speak with your doctor or pharmacist if any of the following continue or become troublesome.

Common glibenclamide side-effectsWhat can I do if I experience this?
Feeling sick (nausea) or being sick (vomiting)Stick to simple foods - avoid rich or spicy meals
Hard stools that are difficult to pass (constipation)Eat a well-balanced diet and drink plenty of water
Loose, watery stools (diarrhoea)Drink plenty of water to replace any lost fluids
Signs of low blood sugar (glucose): feeling shaky or anxious, sweating, looking pale, feeling hungry, feeling that your heart is pounding (palpitations), feeling dizzyEat something containing sugar such as a sweet biscuit or a sugary drink (not diet) and follow this up with a snack such as a sandwich. Tell your doctor if you notice these symptoms
Increase in weightIf this becomes a problem, let your doctor know at your next check-up

If you experience any other symptoms which you think may be due to the tablets, speak with your doctor or pharmacist for further advice.

  • Keep all medicines out of the reach and sight of children.
  • Store in a cool, dry place, away from direct heat and light.

Never take more than the prescribed dose. If you suspect that you or someone else might have taken an overdose of this medicine, go to the accident and emergency department of your local hospital. Take the container with you, even if it is empty.

This medicine is for you. Never give it to other people even if their condition appears to be the same as yours.

Do not keep out-of-date or unwanted medicines. Take them to your local pharmacy which will dispose of them for you.

If you have any questions about this medicine ask your pharmacist.

Further reading & references

Disclaimer: This article is for information only and should not be used for the diagnosis or treatment of medical conditions. EMIS has used all reasonable care in compiling the information but make no warranty as to its accuracy. Consult a doctor or other health care professional for diagnosis and treatment of medical conditions. For details see our conditions.

Original Author:
Helen Allen
Current Version:
Peer Reviewer:
Dr John Cox
Document ID:
3451 (v25)
Last Checked:
Next Review:
The Information Standard - certified member

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