Sulfonylurea-induced hypoglycemia
Sulfonylurea or meglitinide exposure, whether a therapeutic misadventure, an accidental pediatric ingestion, an intentional overdose, or surreptitious administration, forces pancreatic insulin release independent of glucose and causes prolonged or recurrent hypoglycemia. A dextrose bolus alone provokes rebound hypoglycemia; the specific antidote is octreotide, given with a sustained dextrose infusion.
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What this article covers
- Overview
The entity: low blood glucose from excess pancreatic insulin release triggered by a sulfonylurea (glyburide, glipizide, glimepiride) or a meglitinide (repaglinide, nateglinide), whether a therapeutic…
- Epidemiology
Therapeutic misadventure is the most common scenario: an older adult on chronic sulfonylurea therapy whose renal function declines, whose dose is unchanged, or who eats less than usual develops unexpected hypoglycemia.
- Risk factors
Longer-acting agents, especially glyburide: prolonged action and active renally cleared metabolites give the highest hypoglycemia risk among sulfonylureas.
- Pathophysiology
The molecular target is the beta cell's ATP-sensitive potassium channel: sulfonylureas bind its sulfonylurea receptor subunit and close the channel, depolarizing the membrane.
- Clinical features
Hyperadrenergic symptoms come first as glucose begins to fall: palpitations, diaphoresis, tremor, and anxiety, from a catecholamine surge.
- Differential diagnosis
Insulinoma: identical elevated insulin and C-peptide pattern, but the sulfonylurea screen is negative and there is no exposure history.
- Diagnosis
The diagnosis is established by the Whipple triad, symptoms of hypoglycemia, a plasma glucose below 54 mg/dL drawn at the time of symptoms, and prompt relief once glucose is corrected, together with…
- Management
First, address airway, breathing, and circulation: protect the airway in a comatose or seizing patient, and obtain intravenous access.
- Complications
Hypoxic brain injury: from prolonged or severe neuroglycopenia, especially if a dextrose bolus is used without a sustained infusion and octreotide.
- Prognosis
Prognosis is generally favorable with prompt recognition and correct treatment: a sustained dextrose infusion combined with octreotide controls most cases without lasting injury.
- Prevention
Avoid the longest-acting sulfonylurea in older adults and chronic kidney disease: a shorter-acting or non-secretagogue agent is preferred when renal function is reduced.
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