Sulfonylureas
Closing KATP channels on beta cells, so the pancreas releases insulin.
Also called sulphonylureas.
Class card
- Drugs
- Gliclazide, Glimepiride and Glibenclamide
- Used for
- Type 2 diabetes
- Known for
- Low blood sugar (hypoglycemia), sometimes prolonged
- Weight gain
- Name stems
- gli-
4 cards: the class, and each drug in it.
Mechanism of action
How do sulfonylureas work?
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.
The drugs
Sulfonylureas with a card
- GliclazideDiffers from related sulfonylureas in its nitrogen-containing ring and in its mild antiplatelet (hemovascular) effects.
- GlimepirideTaken once a day with the first meal; like all sulfonylureas it causes weight gain.
- GlibenclamideCalled glyburide in the US. Hypoglycemia can be hard to spot in older people and in those taking beta blockers.
Uses
What are sulfonylureas used for?
- Type 2 diabetes
Side effects
Side effects of sulfonylureas
- Low blood sugar (hypoglycemia), sometimes prolongedKnown forSerious
- Weight gainKnown for
- Nausea and other stomach upset
- Rash and itching
- Hemolytic anemia, especially with G6PD deficiencySerious
- Low sodium (hyponatremia)Serious
- Cholestatic jaundice (rare)Serious
- Hepatitis, rarely liver failureSerious
- Blood disorders such as agranulocytosis (rare)Serious
- Flushing with alcohol (disulfiram-like reaction), rare
What the class has in common. Each drug's card has its own, and Known for marks what an exam expects you to know.
Watch for
Cautions
- Avoid in type 1 diabetes, ketoacidosis, and in people allergic to sulfonylureas or sulfonamides.
- Older people and those with kidney or liver disease are prone to severe, prolonged hypoglycemia.
- G6PD deficiency: risk of hemolytic anemia, so a drug from another class is preferred.
- Miconazole, fluconazole, clarithromycin, NSAIDs and alcohol can strengthen their effect and cause hypoglycemia.
Remember them
A way to remember them
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
Name stems
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
Don't mix them up
Classes easily confused with these
Sources
Checked against
Written for biofideX in plain words, after checking these references:
- Glimepiride tablets: label (DailyMed)
- Glyburide tablets: label (DailyMed)
- Gliclazide 30 mg modified-release tablets: SmPC (emc)
- Glyburide (NCI Thesaurus)
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
Practice sulfonylureas with the other classes in this group: what each drug is, how it works, what it treats and what it's known for.
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