Gliclazide

Sulfonylureas

ATC code: A10BB09

Brand names: Gliclazida Cinfa, Gliclazida Normon

Updated 27 May 2026 · Methodology

Indications

Type 2 diabetes mellitus

Second line

Type 2 diabetes with inadequate glycemic control on metformin. Starting dose Diamicron MR 30 mg once daily with breakfast; titrate up to 120 mg. 2024 and Spanish redGDPS 2023 position sulfonylureas as third-line after metformin and SGLT-2 inhibitors or GLP-1 agonists, especially in patients with cardiovascular comorbidities. Gliclazide MR has lower severe hypoglycemia and cardiovascular mortality risk than glibenclamide (ADVANCE trial).

Sources

ICD-10: E11 · ICD-11: 5A11

Marketing claims without evidence base

The drug is promoted for these uses outside international guidelines. Each entry below is analyzed against AEMPS, FDA, EMA, Cochrane and major RCTs.

Weight loss

Not recommended

Gliclazide is a sulfonylurea antidiabetic. It is prescribed for type 2 diabetes as a non-first-line drug ( 2024, 2024). In people without diabetes, gliclazide is not used for weight loss: the drug causes hypoglycemia (life-threatening, especially in people with normal blood sugar), weight gain (paradoxically, via insulin stimulation), and cardiovascular risks. If gliclazide was prescribed for weight loss without diabetes, seek a second opinion immediately.

Sources

How to read tiers A–F

AStrong evidence – first or second line in international guidelines
BRecommended in selected cases
CStudy data contradict each other
DBenefit not proven, no documented harm
FDocumented harm, or risk without benefit

Mechanism of action

A second-generation sulfonylurea. Closes ATP-dependent potassium channels in pancreatic beta-cells, stimulating insulin secretion. Unlike glibenclamide, gliclazide has an additional antiplatelet effect and lower severe hypoglycemia risk. In Spanish practice the modified-release form (Diamicron MR) is widely used – once-daily dosing with a flatter concentration profile and reduced hypoglycemia risk in older patients.

Safety

Contraindications

Gliclazide, other sulfonylurea, or sulfonamide hypersensitivity
Type 1 diabetes
Diabetic ketoacidosis, precoma, or coma
Severe hepatic or renal impairment
Pregnancy and lactation
Age under 18

Serious adverse effects

Severe hypoglycemia with loss of consciousness and seizures (risk lower than glibenclamide)
Cholestatic jaundice (rare)
Agranulocytosis (very rare)

Common adverse effects

Hypoglycemia (sweating, tremor, hunger, confusion)
Weight gain (1–3 kg in the first year)
Nausea
Skin rash

Pregnancy: can you take Gliclazide?

AEMPS summary of product characteristics (section 4.6): there are no or limited data (fewer than 300 pregnancies) on gliclazide use in pregnant women, though some data exist for other sulfonylureas; gliclazide was not teratogenic in animal studies. As a precaution, it is preferable to avoid gliclazide during pregnancy. Diabetes should be controlled before pregnancy to reduce the risk of congenital malformations linked to uncontrolled diabetes. Hypoglycaemic agents are not recommended and insulin is the first-choice treatment for diabetes in pregnancy; the switch to insulin is made before trying to conceive or as soon as pregnancy is diagnosed.

Breastfeeding: can you take Gliclazide?

Contraindicated during lactation – neonatal hypoglycemia risk via breast milk. Alternative – insulin.

Calculate RID

Reference information, not a clinical decision. Discuss feeding pauses or changes with your physician or an IBCLC.

Practical notes

Timing and administration

Diamicron MR is taken once daily with breakfast, swallowed whole (do not split – breaks the modified release). Food intake is required to prevent hypoglycemia. On insulin or sulfonylurea, monitor glucose twice daily for the first month. target individualized: <7% in most, <6.5% in young without comorbidity, <8% in frail older adults.

Drug interactions

Beta-blockers (especially non-selective propranolol) mask adrenergic hypoglycemia symptoms, leaving only sweating. Cardioselective beta-blockers (metoprolol, bisoprolol, nebivolol) are preferred. Fluoroquinolones (ciprofloxacin, levofloxacin) raise hypoglycemia risk. Alcohol, CYP2C9 inhibitors (miconazole, fluconazole, cotrimoxazole) enhance the effect.

Label mentions16 mentions

Verbatim lines from the interaction sections, in the language of the label

From this drug’s label

CriticalMiconazole
«Tratamiento con miconazol (ver sección 4.5).»
AEMPS, section 4.3 · Open on CIMA
Moderateanticoagulantesclass named in the label
«Tratamiento con Anticoagulantes (ej. warfarina): Puede ser necesario el ajuste de la dosis del anticoagulante.»
AEMPS, section 4.5 · Open on CIMA
Moderateantipsicóticosclass named in the label
«Clorpromazina (agente neuroléptico): las dosis altas (> 100 mg de clorpromazina al día) aumentan la glucemia (liberación reducida de insulina) Advertir al paciente y destacar la importancia de la…»
AEMPS, section 4.5 · Open on CIMA
Moderatebetabloqueantesclass named in the label
«Se puede potenciar el efecto reductor de glucosa en sangre y en consecuencia en algunos casos puede producirse hipoglucemia, cuando se toma uno de los siguientes fármacos,: otros tratamientos…»
AEMPS, section 4.5 · Open on CIMA
ModerateCaptopril
«Se puede potenciar el efecto reductor de glucosa en sangre y en consecuencia en algunos casos puede producirse hipoglucemia, cuando se toma uno de los siguientes fármacos,: otros tratamientos…»
AEMPS, section 4.5 · Open on CIMA
ModerateChlorpromazine
«Clorpromazina (agente neuroléptico): las dosis altas (> 100 mg de clorpromazina al día) aumentan la glucemia (liberación reducida de insulina) Advertir al paciente y destacar la importancia de la…»
AEMPS, section 4.5 · Open on CIMA
ModerateClarithromycin
«Se puede potenciar el efecto reductor de glucosa en sangre y en consecuencia en algunos casos puede producirse hipoglucemia, cuando se toma uno de los siguientes fármacos,: otros tratamientos…»
AEMPS, section 4.5 · Open on CIMA
Moderatecorticosteroidesclass named in the label
«Advertir al paciente y destacar la importancia de la monitorización de la glucemia, en particular al inicio del tratamiento. Puede ser necesario ajustar la dosis del fármaco antidiabético durante y…»
AEMPS, section 4.5 · Open on CIMA
ModerateEnalapril
«Se puede potenciar el efecto reductor de glucosa en sangre y en consecuencia en algunos casos puede producirse hipoglucemia, cuando se toma uno de los siguientes fármacos,: otros tratamientos…»
AEMPS, section 4.5 · Open on CIMA
Moderatefibratosclass named in the label
«Se puede potenciar el efecto reductor de glucosa en sangre y en consecuencia en algunos casos puede producirse hipoglucemia, cuando se toma uno de los siguientes fármacos,: otros tratamientos…»
AEMPS, section 4.5 · Open on CIMA
ModerateFluconazole
«Se puede potenciar el efecto reductor de glucosa en sangre y en consecuencia en algunos casos puede producirse hipoglucemia, cuando se toma uno de los siguientes fármacos,: otros tratamientos…»
AEMPS, section 4.5 · Open on CIMA
ModerateIMAOclass named in the label
«Se puede potenciar el efecto reductor de glucosa en sangre y en consecuencia en algunos casos puede producirse hipoglucemia, cuando se toma uno de los siguientes fármacos,: otros tratamientos…»
AEMPS, section 4.5 · Open on CIMA
Moderateinhibidores de la ECAclass named in the label
«Se puede potenciar el efecto reductor de glucosa en sangre y en consecuencia en algunos casos puede producirse hipoglucemia, cuando se toma uno de los siguientes fármacos,: otros tratamientos…»
AEMPS, section 4.5 · Open on CIMA
ModerateMetformin
«Se puede potenciar el efecto reductor de glucosa en sangre y en consecuencia en algunos casos puede producirse hipoglucemia, cuando se toma uno de los siguientes fármacos,: otros tratamientos…»
AEMPS, section 4.5 · Open on CIMA
Moderatequinolonasclass named in the label
«Fluoroquinolonas: En caso de un uso simultáneo de gliclazida y fluoroquinolonas, el paciente debería conocer los riesgos de los cambios en la glucemia y se debería hacer hincapié en la importancia de…»
AEMPS, section 4.5 · Open on CIMA
ModerateWarfarin
«Tratamiento con Anticoagulantes (ej. warfarina): Puede ser necesario el ajuste de la dosis del anticoagulante.»
AEMPS, section 4.5 · Open on CIMA

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Frequently asked

What is Gliclazide used for?

Gliclazide is evaluated for the following indications with varying evidence strength: Type 2 diabetes mellitus (evidence tier A), Weight loss (evidence tier F). See the full indication matrix with dosing and citations above on this page.

What are the side effects of Gliclazide?

Common side effects of Gliclazide (≥ 1 in 100): Hypoglycemia (sweating, tremor, hunger, confusion), Weight gain (1–3 kg in the first year), Nausea, Skin rash. See the Safety section for uncommon and serious reactions.

Is Gliclazide safe during pregnancy?

Is Gliclazide compatible with breastfeeding?

Contraindicated during lactation – neonatal hypoglycemia risk via breast milk. Alternative – insulin.

Can you drink alcohol while taking Gliclazide?

Alcohol, CYP2C9 inhibitors (miconazole, fluconazole, cotrimoxazole) enhance the effect.

Who should not take Gliclazide?

Gliclazide is contraindicated in: Gliclazide, other sulfonylurea, or sulfonamide hypersensitivity; Type 1 diabetes; Diabetic ketoacidosis, precoma, or coma; Severe hepatic or renal impairment; Pregnancy and lactation. Full list in the Safety section.

Official sources

Direct links to regulator labels. Open in a new tab.

AEMPS / CIMALabel dated 07/03/2025

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