Endocrine · Topic 3 of 13

Hypoglycemia

Endocrine · diabetes emergencies

Hypoglycemia

Below 70 mg/dL on insulin or a sulfonylurea: 15 g of glucose if the patient can swallow, IV dextrose or glucagon if not.

Key numbers

Hypoglycemia below 70 mg/dL< 70 mg/dL

Give 15 g oral glucose15 g → recheck 15 min

Cannot swallow: IV 50% dextroseD50 50–100 mL IV

No IV access: glucagon 1 mg IMglucagon 1 mg IM/SC

Sulfonylurea overdose: octreotide plus dextroseoctreotide 50–100 mcg

01 · Defined byHypoglycemia below 70 mg/dL

Level 1: glucose < 70 and ≥ 54 mg/dL. Level 2: < 54 mg/dL (clinically significant). Level 3: severe event with altered mental or physical status needing assistance, at any glucose.

02 · DoGive 15 g oral glucose

A conscious patient who can swallow takes 15 g of glucose (preferred carbohydrate), rechecks in 15 minutes and repeats until glucose is > 70 mg/dL, then eats a meal or snack.

03 · GiveSulfonylurea overdose: octreotide plus dextrose

For sulfonylurea hypoglycemia, give octreotide 50–100 mcg SC every 6–12 h with dextrose: dextrose alone triggers further insulin release and rebound hypoglycemia. Observe at least 12 h after stopping both.

Causes & risk factors

Why it happens

Hypoglycemia unawareness: screen and relax goalsFrequent hypoglycemia, long-standing or type 1 diabetes blunt autonomic warning symptoms; review hypoglycemia and awareness at every visit and raise glycemic goals for at least several weeks to restore awareness.

Inpatient triggers: lost nutrition, steroid taperCommon inpatient triggers: NPO status or interrupted tube feeds or TPN without insulin adjustment, steroid dose reduction, poor intake or vomiting, declining kidney function, and mistimed prandial insulin.

Insulin and sulfonylureas cause most hypoglycemiaInsulin and sulfonylureas (or meglitinides) cause most drug-induced hypoglycemia; use sulfonylureas cautiously in older adults, kidney disease or with insulin. Metformin, SGLT2 inhibitors and GLP-1 RAs alone rarely do.

Presentation

What you'll see

Autonomic warning, then neuroglycopeniaAutonomic symptoms (sweating, tremor, palpitations, anxiety, hunger) begin near 60 mg/dL; neuroglycopenia (confusion, behavior change, seizures, coma) near 50 mg/dL.

Diagnosis & monitoring

Work-up

No diabetes: confirm Whipple triadWithout diabetes treatment, a hypoglycemic disorder requires Whipple triad: hypoglycemic symptoms, plasma glucose < 55 mg/dL at that time, and relief when glucose is raised.

Do right now

In this order

First moves

Give 15 g oral glucose15 g → recheck 15 min

→

Cannot swallow: IV 50% dextroseD50 50–100 mL IV

→

No IV access: glucagon 1 mg IMglucagon 1 mg IM/SC

→

Sulfonylurea overdose: octreotide plus dextroseoctreotide 50–100 mcg

Why each step

Give 15 g oral glucoseA conscious patient who can swallow takes 15 g of glucose (preferred carbohydrate), rechecks in 15 minutes and repeats until glucose is > 70 mg/dL, then eats a meal or snack.

Cannot swallow: IV 50% dextroseIn hospital, give 50% dextrose 50–100 mL IV bolus to the patient who cannot safely swallow, followed by a 5–10% dextrose infusion when hypoglycemia is likely to recur.

No IV access: glucagon 1 mg IMWithout IV access give glucagon 1 mg IM or SC, nasal glucagon 3 mg or dasiglucagon 0.6 mg SC; prescribe glucagon to everyone taking insulin or at high risk of hypoglycemia.

Sulfonylurea overdose: octreotide plus dextroseFor sulfonylurea hypoglycemia, give octreotide 50–100 mcg SC every 6–12 h with dextrose: dextrose alone triggers further insulin release and rebound hypoglycemia. Observe at least 12 h after stopping both.

Management

Orders

Every inpatient value < 70 changes the planEvery hospital needs a hypoglycemia protocol, and each documented glucose < 70 mg/dL should prompt review and change of the insulin or medication plan.

Red flags & don'ts

Avoid harm

Insulin overdose: days of hypoglycemia, low potassium complicationLong-acting insulin overdose can cause hypoglycemia lasting days: titrate a 10–50% dextrose infusion to glucose, monitor potassium, magnesium and phosphate, and avoid overcorrecting potassium.

Glucagon fails when glycogen is depleted avoidGlucagon works by releasing liver glycogen, so it has little effect after prolonged fasting or prolonged hypoglycemia — use IV dextrose instead.

Insulin or sulfonylurea hypoglycemia?

Commonly confused

Serum insulin	High
C-peptide	Low (suppressed)
Key treatment	Titrated IV dextrose infusion
Watch for	Days of hypoglycemia with long-acting insulin; hypokalemia

More detail

Reference

Show 4 reference facts

Without diabetes, consider medications and alcohol, sepsis, liver, kidney or heart failure, adrenal insufficiency, severe undernutrition and, rarely, insulinoma.

CGM goals: time below 70 mg/dL under 4% (under 1% in older adults) and below 54 mg/dL under 1%.

After glucose recovers, a snack with complex carbohydrate and protein prevents recurrence; rebound hyperglycemia can follow from overtreatment and counter-regulatory hormones.

In sulfonylurea overdose, treat documented hypoglycemia with an IV dextrose bolus but avoid prophylactic dextrose infusions; hypoglycemia can be delayed or recur for days.

Pearl

Rule of 15: 15 g of glucose, recheck in 15 minutes, repeat until above 70.

Sources · ADA. 6. Glycemic Goals, Hypoglycemia, and Hyperglycemic Crises: Standards of Care in Diabetes—2026. Diabetes Care 2026;49(Suppl 1) · Merck Manual Professional — Hypoglycemia · ADA. 16. Diabetes Care in the Hospital: Standards of Care in Diabetes—2026. Diabetes Care 2026;49(Suppl 1) · Klein-Schwartz W, Stassinos GL, Isbister GK. Treatment of sulfonylurea and insulin overdose. Br J Clin Pharmacol 2016;81:496–504, doi:10.1111/bcp.12822 (abstract read via Europe PMC) · ADA. 9. Pharmacologic Approaches to Glycemic Treatment: Standards of Care in Diabetes—2026. Diabetes Care 2026;49(Suppl 1) · Merck Manual Professional — Medications for Diabetes Mellitus Treatment · Maryland Poison Center. ToxTidbits Antidote Facts: Octreotide (rev. 2018) · Starter sheet built from the verified AGACNP fact map (facts reviewed 2026-10-15).