Class Explorer · Endocrine
Sulfonylureas
Close the ATP-sensitive potassium channel on the beta cell, depolarising it and forcing insulin release whether or not glucose is high. That last clause is the whole safety story.
Members
GliclazideThe sulfonylurea to choose when a sulfonylurea is what you need.Glyburide (glibenclamide)The long sulfonylurea that older kidneys cannot clear.
Also in this class: Glimepiride · Glipizide. Full pages arrive as the library grows.
Compare the members
Gliclazide
- Duration
- Shorter
- Renal behaviour
- Inactive metabolites, more forgiving
- Note
- Preferred if a sulfonylurea is needed
Glyburide (glibenclamide)
- Duration
- Long
- Renal behaviour
- Active renal metabolites accumulate
- Note
- Avoid in older adults and CKD
Shared across the class
- Indications
- Type 2 diabetes, second-line or where cost dominates
- Adverse effects
- Hypoglycemia · Weight gain
- Contraindications
- Type 1 diabetes · Severe renal or hepatic impairment (agent-dependent)
- Monitoring
- Hypoglycemia symptoms and, if capillary testing is available, values · HbA1c · Renal function, which changes the hypoglycemia risk of the same dose
What makes each agent different
- Glyburide has active renally-cleared metabolites and the longest duration: in an older patient with declining kidneys it is a hypoglycemia engine, and most geriatric prescribing lists name it explicitly as one to avoid.
- Gliclazide is shorter-acting with inactive metabolites and is the sensible choice when a sulfonylurea is genuinely needed.
- Unlike metformin, SGLT2 inhibitors and GLP-1 agonists, no sulfonylurea has shown cardiovascular benefit; they lower glucose and nothing more.
A sulfonylurea taken with a skipped meal is a hypoglycemia waiting for a schedule. Sick-day rules matter as much here as with metformin.
Sulfonylurea hypoglycemia is long. A patient who wakes up with glucose and a sandwich has not been treated, they have been postponed, and they need admission and an infusion.
Last reviewed 2026-08-16 · Goodman & Gilman's The Pharmacological Basis of Therapeutics, 14th ed.