Gliclazide
A second-generation sulfonylurea tablet that stimulates insulin release, used for type 2 diabetes.
Drug card
- Class
- Sulfonylurea
- How it works
- Closing KATP channels on beta cells, so the pancreas releases insulin
- Used for
- Type 2 diabetes
- Known for
- Low blood sugar (hypoglycemia), sometimes prolonged
- Its name
- gli- means a glucose-lowering drug, often a sulfonylurea
Study it as a flashcard, and it comes back before you forget it.
Mechanism of action
How does gliclazide work?
Gliclazide closes KATP channels on beta cells to release insulin, restoring the early (first-phase) insulin response to glucose. Its structure carries a nitrogen-containing ring, and it mildly reduces platelet aggregation. It is broken down in the liver, partly by CYP2C9, to inactive metabolites, with a half-life of about 12 to 20 hours.
Like other sulfonylureas: Sulfonylureas bind the SUR1 subunit of ATP-sensitive potassium (KATP) channels on pancreatic beta cells and close them. Calcium then enters through voltage-gated channels and triggers the release of stored insulin. They need working beta cells, so they do not help type 1 diabetes, and a missed meal while taking them can cause hypoglycemia.
Uses
What is gliclazide used for?
- Type 2 diabetes
Side effects
Side effects of gliclazide
- Low blood sugar (hypoglycemia), sometimes prolongedKnown forSerious
- Abdominal pain
- Diarrhea
- Nausea and vomiting
- Rash and itching
- Severe skin reactions (SJS, TEN, DRESS)Serious
- Blood disorders such as agranulocytosis (rare)Serious
- Hemolytic anemia, especially with G6PD deficiencySerious
- Cholestatic jaundice (rare)Serious
- Raised liver enzymes and hepatitisSerious
- Low sodium (hyponatremia)Serious
- Brief changes in vision at the start of treatment
Known for marks what an exam expects you to know it for.
Watch for
Cautions and what sets it apart
- Contraindicated with miconazole, in severe kidney or liver failure, and when breastfeeding.
- Needs regular meals, breakfast included; severe hypoglycemia can last for days and need glucose in hospital.
- With fluoroquinolones, blood glucose can swing both low and high, especially in older people.
- Avoided in pregnancy, where insulin is the drug of choice.
Good to know: Differs from related sulfonylureas in its nitrogen-containing ring and in its mild antiplatelet (hemovascular) effects.
Remember it
A way to remember it
Sulfonylureas squeeze insulin out of the beta cell: skip a meal and you get a hypo, and the extra insulin adds weight.
They close KATP channels so beta cells release insulin. Hypoglycemia, worst when meals are missed, and weight gain are the two classic side effects.
Written for biofideX
Its name
gli- means glucose-lowering drug, often a sulfonylurea
At the start of a name it mostly marks sulfonylureas: gliclazide, glimepiride, glibenclamide (US glyburide). The same letters sit inside -gliptin, -gliflozin and -glitazone.
- Every drug name stem
Its class
Sulfonylureas
Other sulfonylureas with a card:
Easily mixed up with DPP-4 inhibitors and SGLT2 inhibitors.
Sources
Checked against
Written for biofideX in plain words, after checking these references:
For learning pharmacology, not for treatment decisions: no doses are given, and a prescriber, pharmacist or the product's own label is the word on any one patient. Spotted a mistake? Tell us and we'll correct it.
Diabetes
Gliclazide is one of 14 drugs practiced together here: their classes, how they work, what they treat and what they're known for.
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