Sulfonylureas · Endocrine
Gliclazide
Diamicron®(brand names vary by market)
The sulfonylurea to choose when a sulfonylurea is what you need.
Also: modified release
Mechanism
Closes the beta cell's ATP-sensitive potassium channel, depolarising it and triggering insulin release independently of the glucose level.
Indications
- Type 2 diabetes
Formulations
Dosing concepts
Meals
Taken with food, because the insulin release it forces happens whether or not a meal follows. A dose taken and a meal skipped is a hypoglycemia with a delay fuse.
Renal impairment
Inactive metabolites make it far more forgiving than glyburide as clearance falls, though caution and dose reduction still apply.
Concepts, not prescribing instructions. Practice numbers live in current references and local protocols.
Pharmacokinetics
- Bioavailability
- High
- Half-life
- 10 to 12 h (immediate-release)
- Elimination
- hepatic: Metabolised to inactive compounds, which is the safety advantage over glyburide
- Protein binding
- ~95%
Adverse effects
- Hypoglycemiacommon & serious
- Weight gaincommon
- Gastrointestinal upsetcommon
Contraindications & precautions
Contraindications
- Type 1 diabetes
- Diabetic ketoacidosis
- Severe hepatic impairment
Precautions
- Older adults
- Renal impairment
- Irregular meals or fasting
- Alcohol
Interactions
Monitoring
Capillary glucose and hypoglycemia episodes
The dose-limiting effect
HbA1c
Efficacy · Every 3 to 6 months
Renal function
Changes the hypoglycemia risk of an unchanged dose
Counselling points
- Take it with a meal. If you skip the meal, skip the dose and tell us.
- Learn the symptoms of a low sugar and always carry fast-acting glucose.
- Alcohol makes lows more likely and harder to notice.
- Sick days: if you cannot eat, contact us rather than guessing.
Clinical pearls
- Sulfonylurea hypoglycemia is prolonged and rebounds. A patient found unconscious, treated with glucose and sent home is a re-admission waiting to happen; they need observation and often an infusion.
- It is a secretagogue, so it depends on residual beta-cell function. Waning effect after years is the disease progressing, not the drug failing.
References & review
- Gliclazide product monograph (consult the current version for your market) (monograph)
- Goodman & Gilman's The Pharmacological Basis of Therapeutics, 14th ed. (reference-work)
Last reviewed 2026-08-16 · jurisdiction: global · drug information changes; verify against current references before practice use.