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Gliclazide oral standard release

Updated 2 Feb 2023 | Sulfonylureas


Tablets containing gliclazide.

Drugs List

  • DIAMICRON 80mg tablets
  • gliclazide 160mg tablets
  • gliclazide 40mg tablets
  • gliclazide 80mg tablets
  • GLYDEX 160mg tablets
  • ZICRON 40mg tablets
  • Therapeutic Indications


    Type 2 diabetes (NIDDM) not controlled by diet,weight loss & exercise alone



    Dose should be taken before a meal.

    Initial dose: 40mg to 80mg daily. Increase until adequate control is achieved.
    Maintenance dose: 40mg to 320mg daily. The dose should be titrated according to patient's response.
    Maximum dose: 320mg daily or 160mg per dose.

    When higher doses are required, gliclazide should be taken twice daily, according to the timing of main meals.
    In obese patients or those not showing adequate response to gliclazide alone, additional therapy should be considered.


    Type 2 diabetes mellitus and maturity-onset diabetes
    Children aged 12 to 18 years (unlicensed)
    Initial dose: 20mg once daily with breakfast, titrated to response.
    Maintenance dose: 20mg to 160mg once daily with breakfast.
    Maximum dose: 320mg daily or 160mg per dose.

    The use of gliclazide in children under 18 years should be under specialist management only.

    Additional Dosage Information

    Switching from another oral antidiabetic agent
    Gliclazide standard release tablets can be taken to replace other antidiabetic agents. The dosage and the half-life of the previous drug should be taken into account when switching to gliclazide standard release tablets. Usually a transitional period is not necessary. The starting dose is 40mg to 80mg and this should be adjusted to suit the patient's blood glucose response.

    When switching from a sulfonylurea with a prolonged half-life, a treatment free period of a few days may be necessary to avoid an additive effect of the two products, which may cause hypoglycaemia.

    Combination treatment with other antidiabetic agents
    Standard release gliclazide may be given in combination with biguanides, alpha glucosidase inhibitors or insulin. Patients not adequately controlled with standard release gliclazide may be given concomitant insulin therapy, initiated under close medical supervision.


    Children under 12 years
    Cholestatic jaundice
    Diabetic coma
    Diabetic ketoacidosis
    Diabetic pre-coma
    Severe hepatic impairment
    Severe renal impairment

    Precautions and Warnings

    Children aged 12 to 18 years
    Adrenal insufficiency
    G6PD deficiency
    Glucose-galactose malabsorption syndrome
    Hepatic impairment
    Lactose intolerance
    Pituitary insufficiency
    Renal impairment

    Advise ability to drive or operate machinery may initially be impaired
    Advise patient to take precautions to avoid hypoglycaemia whilst driving
    Some formulations contain lactose
    Monitor dosage closely in presence of renal or hepatic impairment
    Consider dose reduction to prevent hypoglycaemia if dietary intake reduced
    Discontinue if hepatitis develops
    May induce severe hypoglycaemia
    Risk of hypoglycaemia may be increased by exercise or ingestion of alcohol
    Discontinue if cholestatic jaundice occurs
    Pregnancy confirmed: Change patient to insulin treatment
    Advise patient not to take St John's wort concurrently
    Advise patient they have to inform the DVLA of antidiabetic medication
    Advise patients of the warning signs of hypoglycaemia
    Advise patients on adequate dietary control

    This treatment should only be prescribed if the patient is likely to have a regular food intake (including breakfast). Missed meals, low food consumption and consuming food with a low carbohydrate content can increase the risk of hypoglycaemia. Hypoglycaemia is also more likely to occur following prolonged or strenuous exercise, alcohol intake and during low calorie intake diets.

    A reduction in dosage should be considered if the patient has an insufficient calorie or glucose intake.

    Efficacy of gliclazide treatment may diminish over time (secondary failure) and may require dosage adjustment. This may be due to a reduced response to treatment or to progression in the severity of diabetes.

    Some manufacturers contraindicate its use in porphyria, but the Drug Database for Acute Porphyria states that there is insufficient evidence for it to be classified.

    Pregnancy and Lactation


    Gliclazide is contraindicated during pregnancy.

    Manufacturers recommend to avoid gliclazide during pregnancy. There is little experience with the use of gliclazide during pregnancy.

    Animal studies have shown reproductive toxicity.


    Gliclazide is contraindicated during breastfeeding.

    The manufacturers note that it is not known whether gliclazide or its metabolites are excreted in breast milk and there is a possibility of hypoglycaemia in the infant.

    Other sulfonylureas are excreted in breast milk.


    Advise patient to take dose with breakfast and evening meal if daily dose is higher than 160mg (maximum 160mg per dose).

    Patients and family members should be advised on the signs and symptoms of hypoglycaemia, as well as the conditions that predispose to its development.

    Patient should be reminded of the importance of following dietary advice and of taking regular exercise.

    Caution is advised when driving or operating machinery, especially at the beginning of treatment, due to the possibility of hypoglycaemia (e.g. poor concentration, confusion, poor reactions etc.)

    Advise patient to report to DVLA if there is a risk of hypoglycaemia, or if fitness to drive may be impaired due to diabetes complications. Guidance can be found by accessing website.

    Advise patient to avoid St John's wort concurrently.

    Side Effects

    Abdominal pain
    Bullous reactions
    Cholestatic jaundice
    Drug rash with eosinophilia and systemic symptoms (DRESS)
    Increases in hepatic enzymes
    Maculopapular rash
    Stevens-Johnson syndrome
    Toxic epidermal necrolysis
    Visual disturbances


    It is strongly recommended that the UK National Poisons Information Service be consulted on cases of suspected or actual overdose where there is doubt over the degree of risk or about appropriate management.

    The following number will direct the caller to the relevant local centre (0844) 892 0111

    Information may be obtained if you have access to ToxBase the primary clinical toxicology database of the National Poisons Information Service. This is available via password on the internet ( ) or if this is unavailable at the backup site ( ).

    Further Information

    Last Full Review Date: April 2019

    Reference Sources

    Drugs During Pregnancy and Lactation: Treatment Options and Risk Assessment, 3rd edition (2015) ed. Schaefer, C., Peters, P. and Miller, R. Elsevier, London.

    Summary of Product Characteristics: Diamicron 80mg Tablets. Servier Laboratories Limited. Revised December 2016.
    Summary of Product Characteristics: Gliclazide 80mg Tablets. Wockhardt UK Ltd. Revised February 2017.
    Summary of Product Characteristics: Glydex 160mg tablets. Medreich Plc. Revised May 2020.
    Summary of Product Characteristics: Zicron 40mg Tablets. Bristol Laboratories Ltd. Revised May 2017.

    The Norwegian Porphyria Centre (NAPOS).
    Available at:
    Last accessed: 07 January 2021

    NICE Evidence Services Available at: Last accessed: 07 January 2021

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