Gliclazide
NHS information about gliclazide, including what it's used for, who can take it, how to take it and side effects.
What gliclazide is for
Gliclazide is used as a treatment for type 2 diabetes.
Type 2 diabetes happens when your body does not make enough of a hormone called insulin, or the insulin it makes does not work properly (insulin resistance). Without enough insulin, your blood sugar level can get too high (hyperglycaemia).
Gliclazide works by increasing how much insulin your body makes, which helps to lower your blood sugar level.
How to take gliclazide
Gliclazide usually comes as tablets.
How much you need to take depends on how well your body responds to the medicine.
Most people need to take gliclazide once or twice a day. Your dose may need to be changed after you've been taking it for several weeks.
You'll usually take gliclazide long term. Do not stop taking it unless your doctor tells you to.
When taking gliclazide:
- try to take it at the same time each day – if you take it twice a day, this could be once in the morning and once in the evening
- swallow tablets whole with a glass of water
- take your tablets after a meal to help avoid stomach problems
Always check the packet or leaflet that comes with your medicine. Ask a pharmacist or doctor for advice if you’re not sure how to take it or have any problems taking it.
Side effects of gliclazide
Like all medicines, gliclazide can cause side effects, although not everyone gets them.
Common side effects
Common side effects of gliclazide include:
- stomach pain
- diarrhoea
If you take gliclazide it may cause low blood sugar (hypoglycaemia, or a "hypo"). This can make you feel dizzy, feel sick (nauseous), make you sick (vomit), feel very hungry or very tired.
If you get symptoms of a hypo, eat or drink something sugary to raise your blood sugar level quickly. If this happens often, see your GP.
If you feel sleepy or dizzy after taking gliclazide, do not drive, ride a bike or use machinery until you no longer have these symptoms.
More about side effects
These are not all the side effects of gliclazide.
For a full list, see the leaflet that comes with your medicine or search for your medicine on the electronic medicines compendium website.
You can report any side effects you get on the Yellow Card website
Who can and cannot take gliclazide
Most adults and children aged 12 years and over can take gliclazide, but it’s not suitable for everyone.
For example, it may not be suitable for you if:
- you've ever had an allergic reaction or serious side effect from gliclazide or a similar medicine
- you have severe kidney or liver disease
- you have acute porphyria, a condition that can affect the nervous system
Before taking gliclazide, tell your doctor if you have any medical conditions.
Breastfeeding and gliclazide
Tell your doctor if you’re breastfeeding.
Gliclazide is not usually used while breastfeeding. Your doctor may offer a different medicine while you're breastfeeding.
Pregnancy and gliclazide
Tell your doctor if you’re pregnant or trying to get pregnant.
Gliclazide is not usually used during pregnancy. Your doctor may offer you a different medicine while you're pregnant.
Taking gliclazide with other medicines, food and drink
There are some medicines, remedies and supplements that may not mix well with gliclazide.
These include:
- other medicines for high blood sugar, such as insulin
- weight loss medicines, such as semaglutide or tirzepatide (Mounjaro)
- some antibiotics, such as clarithromycin
- some medicines for high blood pressure or heart failure
Before taking gliclazide, tell your doctor if you're taking any other medicines, herbal remedies, vitamins or supplements.
Food and alcohol with gliclazide
Follow your doctor’s advice about diet while taking gliclazide to reduce the chances of your blood sugar level getting too low. This may include eating a healthy diet and not skipping or delaying meals.
It’s best not to drink alcohol while taking gliclazide because it can affect your blood sugar level.
Find out more about your medicine
To find out more about your medicine, you can:
- check the leaflet that comes with it
- search for your medicine leaflet on the electronic medicines compendium website
- speak to a pharmacist or doctor for advice - if you recently started taking it, you can get help with newly prescribed medicines from a pharmacist as part of the New Medicine Service
