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EMA Cited · Endocrine · Altered mental status

Hypoglycemia

Updated Oct 30, 2026Adults · ED management16 sources · 11 checked in PubMed2 figuresADA 2026 · JBDS 2023

Bottom line

  • Treat any glucose under 70 mg/dL (3.9 mmol/L). Under 54 mg/dL is level 2. Altered mental status that needs someone else's help is level 3, whatever the number.1
  • Awake and able to swallow: 15–20 g of fast glucose by mouth, then recheck in 10–15 minutes.1,2
  • Can't swallow safely: IV glucose, or glucagon 1 mg IM if there is no line. In an ED trial, 10% dextrose woke patients as fast as 50% (median 6 minutes) with less total glucose.2,4,7
  • Sulfonylureas and long-acting insulin cause recurrence. The risk can last 24–36 hours. Over a third of sulfonylurea patients had another low in hospital.2,13
  • Before they leave: a long-acting carbohydrate meal, a glucagon prescription for anyone on insulin, and a treatment-plan review after any level 2 or 3 event.1,2

Levels

Level 154–69mg/dL
Level 2< 54mg/dL
Level 3Needs help

ADA classification. Level 1 is 3.0–3.8 mmol/L; level 2 is under 3.0 mmol/L. Level 3 is a severe event with altered mental or physical function that needs another person's help, at any glucose level.1 The UK JBDS guideline treats anything under 4.0 mmol/L (72 mg/dL).2

  • Symptoms include shakiness, irritability, confusion, tachycardia, sweating and hunger. Neuroglycopenic symptoms begin at level 2.1
  • Level 2 without symptoms suggests impaired hypoglycemia awareness.1
  • Who is at risk: people taking insulin, sulfonylureas or meglitinides. Clinically significant lows are rare with other diabetes drugs.1
  • Major risk factors include a level 2 or 3 event in the past 3–6 months, intensive insulin therapy, impaired awareness, kidney failure, cognitive impairment and food insecurity.1

First steps

  1. Check the glucose and start ABCDE. Stop any insulin infusion that is running.2
  2. Awake and can swallow: give 15–20 g of fast-acting glucose. Recheck in 10–15 minutes and repeat if still low.1,2
  3. Not safe to swallow, with IV access: give 15–20 g of IV glucose. Recheck in 10 minutes.2
  4. No IV access: glucagon 1 mg IM, or 3 mg intranasal. Keep trying for a line.2,7,8
  5. Once awake, feed them: 20 g of long-acting carbohydrate, or 40 g after glucagon.2
  6. Find the cause: which drug, which dose, any overdose, kidney function, food intake, alcohol.1,2,3
FIG 1 · Decision flowCited
  1. Glucose under 70 mg/dL (3.9 mmol/L). Start ABCDE and stop any insulin infusion.1,2
  2. Awake and able to swallow?
    Yes
    15–20 g of fast glucose by mouth. Recheck in 10–15 minutes; repeat if still low.1,2
  3. No
    IV access?
    No
    Glucagon 1 mg IM, or 3 mg intranasal.7,8 Repeat after 15 minutes if no response.7
    Less reliable with starvation, alcohol, liver disease or a sulfonylurea. Keep trying for IV access.2,7
  4. Yes
    IV glucose 15–20 g: 10% glucose 200 mL or 20% glucose 100 mL over 15 minutes. The US label for 50% dextrose gives 10–25 g (20–50 mL).2,6
  5. Recheck at 10 minutes and repeat the IV glucose if still low.2
  6. Feed once awake: 20 g of long-acting carbohydrate, or 40 g after glucagon.2
  7. Sulfonylurea, long-acting insulin, or an overdose?
    Yes
    Expect recurrence for 24–36 hours. Admit and monitor glucose.2,12,13,14
    Sulfonylurea: consider octreotide with dextrose; dose per toxicology or institutional protocol.10,11
  8. No
    No diabetes?
    Yes
    Look for the cause: drugs, critical illness, hormone deficiency, tumors. If endogenous insulin is suspected, draw insulin, C-peptide, proinsulin, beta-hydroxybutyrate and a sulfonylurea screen during the low.3
  9. No
    Before discharge: they have eaten, glucagon is prescribed if they take insulin, and a level 2 or 3 event prompts a treatment-plan review.1,2
FIG 1Hypoglycemia in the ED. Drawn for this page from the ADA 2026 Standards, the JBDS 2023 guideline and the FDA labels cited below. Each box carries its own citations.1,2,6,7

Treatment

TreatmentAdult doseNotes
Can swallow
Oral glucose (tablets, gel, juice)15–20 g; recheck in 10–15 minPure glucose is best. Avoid high-fat or high-protein foods first. With acarbose, use pure glucose only.1,2
Can't swallow safely
Glucose 10% IV200 mL (20 g) over 15 minPreferred by JBDS. Use the smallest volume in kidney or heart failure.2
Glucose 20% IV100 mL (20 g) over 15 minPreferred by JBDS.2
Dextrose 50% IV10–25 g (20–50 mL)US label dose for insulin hypoglycemia; repeat if needed. Hypertonic: extravasation can cause tissue damage.2,6
Glucagon IM, SC or IV1 mg; repeat once after 15 minWorks only with liver glycogen to release. Give glucose instead in starvation, adrenal insufficiency or chronic hypoglycemia.7
Glucagon intranasal3 mg into one nostrilLabeled for severe hypoglycemia.8 Success in 98.7% vs 100% for IM, a few minutes slower (16 vs 13 min).9
After recovery
Long-acting carbohydrate20 g; 40 g after glucagonFor example, two biscuits, a slice of bread, or a meal.2
Octreotide (sulfonylurea)Per toxicology or institutional protocolAdjunct to dextrose, not a substitute.10,11

Unreviewed doses. Verify against the current label and your institution's protocol before giving anything.

Sources disagree

Which IV glucose? The UK JBDS guideline prefers 10% or 20% glucose because 50% is hypertonic and can cause extravasation injury.2 The US 50% dextrose label gives 10–25 g.6 In an ED trial of 5 g boluses (n = 204), 10%, 25% and 50% all restored GCS 15 in a median 6 minutes, and the 10% and 25% arms needed less glucose (median 10 g vs 15 g).4 In EMS patients, 50% gave higher glucose levels on arrival (129.5 vs 108.0 mg/dL) but no difference in re-treatment.5

  • Glucagon is a fallback when there is no IV access. JBDS notes slower recovery and more failures than IV glucose, and it is less likely to work a second time.2
  • Glucagon can backfire in insulinoma by triggering insulin release; give glucose if symptoms return.7
  • Don't stop the next insulin dose in a patient with diabetes. The dose about to be given is usually not the one that caused the low, but the regimen needs review.2

Sulfonylureas, long-acting insulin and overdose

  • Sulfonylurea hypoglycemia is a hospital problem. In 185 patients brought in with it (mean age 71), only 33% had an eGFR over 60. Over a third had another low in hospital, and 13 were readmitted with hypoglycemia within 28 days.13
  • Risk persists for up to 24–36 hours after the last sulfonylurea or long-acting insulin dose, especially with kidney impairment. Keep checking glucose for at least 24–48 hours.2
  • Octreotide added to standard therapy in sulfonylurea hypoglycemia (n = 40) kept glucose higher for the first 8 hours, with fewer recurrent lows.10 A review of animal and human data supports octreotide with supplemental dextrose.11
  • Sulfonylurea overdose: LITFL advises 8 hours of observation for standard tablets and 12 hours for modified-release, then clearance only if well and euglycemic. Onset with extended-release forms can be delayed up to 48 hours. Don't give dextrose before hypoglycemia occurs, because it muddies the risk assessment. A single tablet can cause dangerous hypoglycemia in a child.12
  • Insulin overdose: in 17 intentional overdoses, patients without diabetes were more likely to become and stay hypoglycemic. The IV glucose needed rose with the insulin dose, and lows came later than the insulin's usual duration predicted.14
FIG 2How long the danger lasts. Drawn for this page from cited sources. Overdose observation times are from LITFL, recurrence risk and monitoring from JBDS, and the octreotide effect from one 40-patient trial.2,10,12 Times vary between patients and drugs.

Causes to look for

  • Diabetes treatment with insulin or an insulin secretagogue is the most common cause of hypoglycemia.3
  • Iatrogenic lows in the ED are common. In 591 ED patients with hypoglycemia, 17% were iatrogenic. Insulin given in the ED caused 61% of these, most often for hyperkalemia (45 patients). Unrecognized malnutrition caused the rest.15
  • Watch patients at risk even without insulin, such as those who are intoxicated with alcohol or malnourished.15
  • No diabetes: document Whipple's triad (symptoms, a low glucose, and relief when glucose is raised) before working it up. Look first for drugs, critical illness, hormone deficiency and non-islet-cell tumors.3
  • Suspected endogenous hyperinsulinism: during the low, measure glucose, insulin, C-peptide, proinsulin, beta-hydroxybutyrate and oral hypoglycemic agents, and send insulin antibodies.3

Disposition

  • Admit for sulfonylurea or long-acting insulin hypoglycemia, intentional overdose, and lows that recur despite treatment.2,12,13,14
  • Discharge only after the patient has eaten a long-acting carbohydrate and is staying in range.2
  • Prescribe glucagon for everyone taking insulin or at high risk. Ready-to-use or intranasal products are preferred over kits that need mixing.1
  • Flag the event. One or more level 2 or 3 episodes should prompt a review of the treatment plan, including deintensifying or switching drugs.1
  • Repeat visits are uncommon. Of 791 adults treated by paramedics for hypoglycemia, 5.4% returned to EMS or the ED within 72 hours, and 8 of those 43 returns were for hypoglycemia. Insulin users were less likely to return (adjusted OR 0.4).16

Pitfalls

  • Discharging a sulfonylurea patient after one good glucose.2,13
  • Treating first with foods high in fat or protein. Fat slows the glucose response, and protein can raise insulin secretion.1
  • Relying on glucagon in a malnourished, alcohol-using or adrenally insufficient patient.2,7
  • Giving insulin for hyperkalemia and walking away. That was the commonest iatrogenic cause of ED hypoglycemia.15
  • Giving prophylactic dextrose in an asymptomatic sulfonylurea overdose, which masks the time course.12
  • Forgetting the glucagon prescription at discharge.1

How strong is the evidence?

The ADA rates oral glucose treatment as level B and glucagon prescribing as level A.1 The IV glucose evidence comes from small trials and cohorts.2,4,5 The octreotide trial had 40 patients.10 Overdose observation times are expert advice, not trial results.12

On-shift teaching

Questions to ask a learner at the bedside. Tap a question to see the answer. Every answer uses facts cited above.

Q1What are the three ADA levels of hypoglycemia?
Level 1: 54–69 mg/dL. Level 2: under 54 mg/dL, where neuroglycopenic symptoms begin. Level 3: a severe event with altered mental or physical function needing someone else's help, at any glucose.1
Q2Is D10 as good as D50 for a confused hypoglycemic patient?
In an ED trial of 5 g boluses, 10%, 25% and 50% all restored GCS 15 in a median 6 minutes, and the 10% and 25% arms used less glucose (median 10 g vs 15 g).4 JBDS prefers 10% or 20% because 50% is hypertonic and can cause extravasation injury.2
Q3When might glucagon fail?
It needs liver glycogen to work, so it may fail in starvation, adrenal insufficiency or chronic hypoglycemia.7 JBDS also lists alcohol use, chronic liver disease and sulfonylurea treatment.2
Q4Why admit an older patient with sulfonylurea hypoglycemia who now looks fine?
The risk can last 24–36 hours, especially with kidney impairment.2 Over a third of these patients had another low in hospital.13
Q5What does octreotide add in sulfonylurea hypoglycemia?
Added to standard therapy, it kept glucose higher for the first 8 hours with fewer recurrent lows.10 It goes with dextrose, not instead of it.11
Q6What is the most common cause of hypoglycemia that we cause in the ED?
Insulin given in the ED, most often for hyperkalemia. Iatrogenic causes made up 17% of ED hypoglycemia in one series.15

References

Evidence base

What this page is built on

16 sources, cited 108 times. Dots are sources, filled by how far each was read; stronger color means a larger share of the citations. Tap a tier to see its sources.

Read in full · 6Abstract read · 10Record only · 0Link checked · 0

Checked by the writer, not a physician. The dots show how each source was read, not that anyone has confirmed the claims.

How this page was made
  • Written from scratch. No source text was copied; facts are restated and cited.
  • The ADA 2026 Standards (section 6) and the JBDS 2023 guideline were read in full. The Endocrine Society guideline was available only as its PubMed abstract.
  • Doses come from the JBDS guideline and FDA labels on DailyMed. No label or guideline we could read gives an octreotide dose for sulfonylurea hypoglycemia, so none is given.
  • Each PubMed citation was resolved through NCBI E-utilities and checked against its abstract.
  • Sources searched: PubMed, ADA, JBDS, DailyMed, LITFL. Other FOAM pages on hypoglycemia could not be reached, so they are not cited.
  • Covers adults. Children are dosed differently; follow pediatric guidance. Both figures were drawn for this page from cited sources.
  • Not for clinical use.
Not for clinical use

AI-generated draft. Not reviewed by a physician. This page is for education only and may contain errors, including in doses. Do not use it to diagnose, treat or make decisions about any patient. Rely on your own clinical judgment, your institution's protocols and current drug labeling. Reading this page does not create a physician-patient relationship. Full terms