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Gliclazide (sulfonylurea, antidiabetic agent)

Written by Stephanie Nera, RPh, PharmD · Pharmacology

Updated Jul 24, 2021

Gliclazide is a generic drug under the sulfonylurea class. Sulfonylureas treat hyperglycemia or high blood sugar. Only those with type 2 diabetes can use this drug; it is not for patients with type 1 diabetes.


What is gliclazide used for?

It lowers blood sugar levels in people with type 2 diabetes mellitus, along with diet and exercise.

How should I take gliclazide?

Read the directions on the packaging for complete information. Check the label and expiration date.

For oral dosage forms, swallow it whole without chewing, crushing, or dissolving it in liquid. Take it with meals to prevent gastric irritation.

How do I store gliclazide?

This product is best stored at room temperature away from direct light and moisture. To prevent drug damage, you should not store it in the bathroom or the freezer. 

There may be different brands of this drug that may have different storage needs. So, it is important to always check the product package for instructions on storage, or ask your pharmacist. For safety, you should keep all medicines away from children and pets.

You should not flush this product down the toilet or pour them into a drain unless instructed to do so. Additionally, it is important to properly discard this product when it is expired or no longer needed. Consult your pharmacist for more details about how to safely discard your product.

Precautions & warnings

What should I know before using gliclazide?

Before using this drug, tell your doctor if you are/have:

  • Pregnant or breastfeeding.
  • Taking any other medicines. This includes any prescription, OTC, and herbal remedies.
  • An allergy to any of the ingredients of this product.
  • Any other illnesses, disorders, or medical conditions.
  • Is it safe during pregnancy or breastfeeding?

    This drug is not safe to take during pregnancy or while breastfeeding. Other drugs for lowering blood sugar are preferred.

    Please always consult with your doctor to weigh the potential benefits and risks before taking any medication.

    Side effects

    What side effects can occur from gliclazide?

    Like all drugs, this drug may have side effects. If they occur, side effects are generally mild and resolve once treatment is finished or the dose is lowered. Some reported side effects include:

    • Hypoglycemia (low blood sugar)
    • Hyperglycemia (high blood sugar)
    • Headache
    • Irritability
    • Drowsiness
    • Dizziness
    • Abdominal pain
    • Nausea
    • Diarrhea
    • Skin rash
    • Cough
    • Sweating
    • Increased blood pressure
    • Rapid heartbeat
    • Increased risk of infection
    • Hemolytic anemia (rare)

    However, not everyone experiences these side effects. In addition, some people may experience other side effects. So, if you have any concerns about a side effect, please consult your doctor or pharmacist.


    What drugs may interact with gliclazide?

    This medication may interact with other drugs that you are currently taking, which can change how your drug works or increase your risk for serious side effects. 

    To avoid any potential drug interactions, you should keep a list of all the drugs you are using (including prescription drugs, nonprescription drugs, and herbal products) and share it with your doctor and pharmacist. 

    Drugs with known interactions:

    • Phenylbutazone
    • Chloramphenicol
    • Anticoagulants
    • Other antidiabetic agents
    • Beta blockers
    • Beta agonists
    • Fluconazole
    • Salicylates
    • ACE inhibitors
    • H2-receptor blockers (antacids)
    • MAOIs
    • Sulfonamides
    • Quinolones
    • Clarithromycin
    • NSAIDs
    • Glucocorticoids
    • Danazol
    • Chlorpromazine

    If you experience an adverse drug interaction, inform your doctor immediately to reevaluate your treatment plan. Approaches include dose adjustment, drug substitution, or ending therapy.

    Does food or alcohol interact with gliclazide?

    This drug may interact with food or alcohol by altering the way the drug works or increase the risk for serious side effects. It is best taken with meals. Please discuss with your doctor or pharmacist any potential food or alcohol interactions before using this drug.

    What health conditions may interact with gliclazide?

    This drug may interact with underlying conditions. This interaction may worsen your health condition or alter the way the drug works. Therefore, it is important to always let your doctor and pharmacist know all the health conditions you currently have, especially:

    • Liver impairment
    • Kidney impairment
    • Type I diabetes


    The information provided is not a substitute for any medical advice. You should ALWAYS consult with your doctor or pharmacist before using any medication.

    What is the dose of gliclazide for an adult?

    At first, the recommended dose may be 40 – 80 mg a day. Your doctor may increase your dose if your blood sugar level does not come down enough. The maximum daily dose is 320 mg. You should not take more than your doctor tells you.

    When the total daily dose exceeds two tablets, it should be divided into two equal doses taken morning and evening.

    The medicine should be taken immediately after food, either with breakfast or the main meal of the day.

    What is the dose of Gliclazide for a child?

    The dosage has not been established in pediatric patients. It may be unsafe for your child. It is always important to fully understand the safety of the drug before using. Please consult with your doctor or pharmacist for more information.

    How is Gliclazide available?

    Gliclazide is available in the following dosage forms and strengths:

    • Tablet 80mg

    What should I do in case of an emergency or overdose?

    In case of an emergency or an overdose, call your local emergency services or go to the nearest emergency room.

    What should I do if I miss a dose?

    If you miss a dose, take it as soon as possible. However, if it is almost time for your next dose, skip the missed dose and take your regular dose as scheduled. Do not take a double dose.


    Hello Health Group does not provide medical advice, diagnosis or treatment.

    Written by

    Stephanie Nera, RPh, PharmD


    Updated Jul 24, 2021

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