DurgicalDurgical
EN
Open the app

Pharmacology · Sulfonylureas

Glibenclamide !

A potent, long-acting sulfonylurea: it forces the pancreas to release insulin and carries the highest risk of hypoglycemia in its class.

Updated 2026-11-01

  • Class: Sulfonylureas
  • Ion channel: Sulfonylurea receptor 1 (SUR1) of the KATP channel
  • ATC code: A10BB01

Also called: glyburide

The figure shows glibenclamide bound to SUR1 in the complete KATP channel (hamster SUR1 with rat Kir6.2, proteins very similar to the human ones).

Target in 3D: Sulfonylurea receptor 1 (SUR1) of the KATP channel. PDB structure 6BAA (RCSB PDB, public domain). View the structure at RCSB PDB

Mechanism of action

Glibenclamide binds SUR1 with high affinity and closes the KATP channel of the beta cell. The membrane depolarizes, L-type calcium channels open and insulin is released whatever the glucose level. Its active metabolites and tight binding make the effect long, which is why hypoglycemia with glibenclamide can be severe and recurrent.

  1. Binds SUR1 on the beta-cell KATP channel
  2. The channel closes and the membrane depolarizes
  3. Calcium channels open and insulin granules are released
  4. Glucose falls, even when it is already low

Pharmacokinetics

Absorption
Oral, well absorbed.
Distribution
Highly bound to plasma proteins.
Metabolism
In the liver to metabolites that keep some activity.
Elimination
Bile and urine; kidney or liver failure raises levels and hypoglycemia risk.

Indications

Adverse effects

Common

  • Hypoglycemia
  • Weight gain
  • Nausea, heartburn, fullness
  • Rash, itching, hives

Contraindications

  • Type 1 diabetes
  • Diabetic ketoacidosis
  • Use together with bosentan
  • Hypersensitivity to the drug

Key interactions

Insulin and other glucose-lowering drugs
Add to hypoglycemia.
Beta-blockers
Can increase the effect and blunt the warning signs of hypoglycemia.
NSAIDs and salicylates, sulfonamides, fluoroquinolones, oral azole antifungals (miconazole)
Can increase the glucose-lowering effect and cause severe hypoglycemia.
Alcohol
Raises the risk of hypoglycemia.
Bosentan
Contraindicated: liver enzyme rises when combined.

What is monitored

  • Capillary glucose, especially at the start and in older adults
  • HbA1c
  • Kidney and liver function

Administration and safety

  • Oral tablet, given with a meal (usually breakfast); a skipped meal raises hypoglycemia risk.
  • Look-alike names: glipizide, glyburide (glibenclamide) and glimepiride are easily confused.
  • Often held while the patient is fasting (nil by mouth) in hospital.

Nursing care

  • Before: capillary glucose, kidney and liver function, meal intake, age.
  • During: signs of hypoglycemia (sweating, tremor, confusion); beta-blockers can mask them.
  • After a hypoglycemia episode: glucose is rechecked for many hours, because it can come back.
  • Teach: carry fast sugar, avoid skipping meals, limit alcohol.

Pregnancy and breastfeeding

Insulin is the usual choice. A sulfonylurea taken near delivery can cause prolonged hypoglycemia in the newborn.

Test yourself

Think of the answer, then tap the question to see it.

Why is glibenclamide avoided in frail older adults?

Its long action and active metabolites, plus reduced kidney function with age, make severe and prolonged hypoglycemia more likely.

What blood disorder can sulfonylureas trigger in G6PD deficiency?

Hemolytic anemia.

A patient on glibenclamide is treated for hypoglycemia and wakes up. Can the team relax?

No. Hypoglycemia can return for many hours as the drug keeps acting, so glucose is rechecked repeatedly and glucose support may be needed.

Add to my cards (3)

← Back to the class: Sulfonylureas

Educational content on how drugs work; not a prescribing guide and no substitute for a health professional's advice. No doses are given.

Sources: Glyburide: MedlinePlus Drug Information (MedlinePlus (U.S. National Library of Medicine), 2026); DailyMed - GLYBURIDE tablet (DailyMed (U.S. National Library of Medicine), 2026); Cryo-EM structure of the pancreatic beta-cell KATP channel bound to ATP and glibenclamide (RCSB Protein Data Bank, 2017); ATCDDD - ATC/DDD Index (WHO Collaborating Centre for Drug Statistics Methodology, 2026).

Spotted a mistake?We are always improving for the community. Tell us what is wrong and our team will review it.Report a mistake

Representative model, for educational purposes only.