A long-acting sulfonylurea for type 2 diabetes
Glibenclamide
A long-acting diabetes tablet that lowers blood sugar by prompting the pancreas to make more insulin.
What is Glibenclamide?
Glibenclamide is a long-acting sulfonylurea, a type of tablet for type 2 diabetes that lowers blood sugar by prompting the pancreas to release more insulin. Because it works for a long time, its main concern is prolonged low blood sugar (hypoglycaemia), which can be serious and is more likely in older people and those with reduced kidney function; for this reason it is often avoided in older people and shorter-acting alternatives are preferred. It can also cause weight gain. It is usually taken with food, and people are taught how to recognise and treat low blood sugar.
Education and reference only. This is a plain-language guide to Glibenclamide — it deliberately contains no doses. Doses depend on the person, the brand and the reason for treatment, and belong with your prescriber. Always check the BNF, the product labelling (SmPC) and follow medical advice.
What it is
Glibenclamide is a tablet for type 2 diabetes belonging to the sulfonylurea group. These medicines lower blood sugar by encouraging the pancreas to produce more insulin. Glibenclamide is one of the longer-acting members of the group, which is both its defining feature and its main drawback. Because longer action means a greater and more prolonged risk of low blood sugar, it is now used less often, and shorter-acting sulfonylureas tend to be preferred, especially in older people. It is taken by mouth, usually with food.
How it works
Glibenclamide stimulates the insulin-producing cells in the pancreas to release more insulin, the hormone that moves sugar from the blood into the body's cells. This lowers the level of sugar in the blood. Because glibenclamide is long-acting, this boost to insulin release continues for many hours, which keeps blood sugar down but also means that if a meal is missed or the dose is high, blood sugar can fall too low and stay low for a prolonged time. This is why it carries a higher risk of significant low blood sugar than shorter-acting options.
Company & origin
Originated / developed by: Generic.
A long-acting sulfonylurea used in the UK for type 2 diabetes, now used cautiously and generally avoided in older people.
What it treats
Conditions Glibenclamide is used for
Practical use
How to take Glibenclamide
General, dose-free guidance — always follow your prescriber's and the leaflet's specific instructions.
- Take it by mouth with or just before food, usually with breakfast or your first main meal, as advised.
- Eat regular meals and avoid skipping them, as missing food makes low blood sugar more likely.
- Learn the warning signs of low blood sugar and always carry something sugary to treat it.
- Be careful with alcohol, which can increase the risk of low blood sugar.
- Tell your team if you become unwell, eat less, or have kidney problems, as the dose may need changing.
Weighing it up
Advantages & disadvantages of Glibenclamide
Advantages
- An effective, long-established tablet for lowering blood sugar in type 2 diabetes.
- Taken by mouth, usually once or twice a day with food.
- Works by using the body's own pancreas to release more insulin.
Disadvantages
- Carries a higher and more prolonged risk of low blood sugar than shorter-acting options.
- Often avoided in older people and those with reduced kidney function because of this risk.
- Can cause weight gain.
Practical use
Good to know
The dominant safety point with glibenclamide is the risk of low blood sugar (hypoglycaemia), and because the medicine is long-acting, an episode can be prolonged and may come back. Warning signs include shaking, sweating, hunger, confusion and feeling lightheaded; everyone taking it should know how to recognise and treat this quickly, usually with a sugary drink or snack followed by some longer-lasting carbohydrate. The risk is higher in older people and in those whose kidneys are not working well, which is the main reason glibenclamide is often avoided in older people in favour of shorter-acting alternatives. Another common effect is weight gain. Taking it with food, eating regularly, and being careful with alcohol all help reduce the chance of low blood sugar. Tell your team if you become unwell or are eating less, as the dose may need adjusting.
Who should not take it / use with caution
- People who have had a serious allergic reaction to glibenclamide should not take it.
- It is generally avoided in older people because of the prolonged risk of low blood sugar.
- It is avoided or used with great care in people with significant kidney or liver problems.
- It is not used for type 1 diabetes, and the team decides on its use in pregnancy.
Monitoring
- Checking blood sugar control, including HbA1c over time and home monitoring where used.
- Watching for episodes of low blood sugar, especially in older people and those with kidney problems.
- Reviewing kidney function and weight during treatment.
Side effects
- Low blood sugar (hypoglycaemia), which can be prolonged because the medicine is long-acting.
- Weight gain.
- Stomach upset such as nausea, and occasionally skin reactions.
- Rarely, changes in blood counts or liver tests, which should be reported.
Key interactions
- Other diabetes medicines and insulin add to the blood-sugar-lowering effect and the risk of going too low.
- Alcohol can increase the risk of low blood sugar.
- Several other medicines can raise or lower its effect, so tell your prescriber everything you take.
Available as: Tablets taken by mouth.
Answers
Glibenclamide: frequently asked questions
What is glibenclamide used for?
It is a sulfonylurea tablet used to treat type 2 diabetes, lowering blood sugar by prompting the pancreas to release more insulin.
Why is it riskier in older people?
Because it is long-acting, low blood sugar can be prolonged and more serious, which is more likely in older people and those with reduced kidney function, so it is often avoided in them.
What are the signs of low blood sugar?
Shaking, sweating, hunger, confusion and feeling lightheaded; treat it quickly with something sugary and tell your team if it happens.
Does it cause weight gain?
Yes, weight gain is a recognised side effect of glibenclamide, as with other sulfonylureas.
Should I take it with food?
Yes, it is usually taken with or just before a meal, and eating regularly helps reduce the risk of low blood sugar.
The wider class
About Sulfonylurea (type 2 diabetes)
Glibenclamide belongs to the sulfonylurea (type 2 diabetes) class. For how the class as a whole works, its shared safety principles and monitoring, see the full guide.
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Authoritative sources
- BNF
- NICE CKS
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