Sounds like 'gli-cla-zide'

Easy-to-read medicine information about gliclazide – what it is, how to take gliclazide safely and possible side effects.

Type of medicine Also called
  • Anti-diabetic medication (to treat diabetes)
  • Belongs to a group of medicines called sulphonylureas
  • Apo-Gliclazide®
  • Glizide®

What is gliclazide?

  • Gliclazide is used to treat diabetes.
  • It works by increasing the amount of insulin produced by the pancreas and in this way lowers high blood sugar.
  • It is one of a group of medicines known as sulphonylureas.


  • The dose of gliclazide will be different for different people.
  • Your doctor will usually start you on a low dose and increase the dose gradually, depending on your blood sugar level. This allows your body to get used to the medicine and reduces unwanted side effects.
  • Always take your gliclazide exactly as your doctor has told you. The pharmacy label on your medicine will tell you how much gliclazide to take, how often to take it, and any special instructions.

How to take gliclazide

  • Take gliclazide at the same times each day.
  • Gliclazide is best taken just before breakfast, or your first main meal of the day.
  • If you require higher doses, you may split the dose and take gliclazide twice a day, before breakfast and before your evening meal.
  • Do not skip meals while taking gliclazide.
  • Limit or avoid drinking alcohol while you are taking gliclazide. It may cause you to feel sick (headache, stomach pains).
  • If you forget to take your dose, take it as soon as you remember that day.
  • But, if it is nearly time for your next dose, just take the next dose at the right time. Do not take double the dose.
  • Keep taking gliclazide every day, to control your diabetes. Do not stop taking gliclazide suddenly; speak to your doctor or nurse before stopping.

Special instructions

  • Sometimes gliclazide may lower your blood sugar too much - called hypoglycaemia. This may cause you to feel weak, faint, dizzy, drowsy or irritable. You may get a headache, tremor (shakes) or blurred vision.
  • If this occurs, drink something sweet such as a small glass of sweetened soft drink, or fruit juice or eat something sweet such as lollies.
  • Follow this up with a snack such as a sandwich.
  • Tell your doctor or nurse if this happens.

Possible side effects

Like all medicines, gliclazide can cause unwanted side effects, although not everyone gets them. Often unwanted side effects improve as your body gets used to the new medicine.

Side effects What should I do?

  • Feeling sick (nausea) or vomiting
  • Diarrhoea
  • Constipation

  • These are quite common when you first start taking gliclazide and usually go away with time.
  • Tell your doctor if troublesome. 

  • Signs of an allergic reaction such as skin rashes, itching, redness or swelling of the face, lips, mouth or have problems breathing.
  • Tell your doctor immediately or ring Healthline on 0800 611 116
  • Signs of low blood sugar such as headache, dizziness, tremor, sweating, hunger, irritability, weakness, feeling shaky or anxious. 
  • Drink something sweet such as a small glass of sweetened soft drink, or fruit juice or eat something sweet such as lollies.
  • Tell your doctor.


Gliclazide may interact with a number of important medications and herbal supplements so check with your doctor or pharmacist before starting gliclazide or before starting any new medicines.

Learn more

Medsafe Consumer Information Sheet: glizide

New Zealand Formulary Patient Information: Gliclazide

Credits: Sandra Ponen, Pharmacist. Reviewed By: Dr Janine Bycroft, GP Last reviewed: 19 Jun 2014