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Sulfonylurea-induced hypoglycemia in an elderly patient

Myrna Klein, age 82, is admitted to the medical-surgical unit from the emergency department (ED) at 9 pm for an exacerbation of chronic obstructive pulmonary disease. She also has hypertension, diabetes type 2, and mild dementia. Ted, her nurse, obtains her initial vital signs: heart rate 89 beats per minute (bpm), blood pressure 145/71 mm Hg, respiratory rate 10 breaths/minute, oxygen saturation 95% on 2 L oxygen, and temperature 97.7° F (36.5° C). Her blood glucose (BG) level is 90 mg/dL.

History and assessment hints

Mrs. Klein tells Ted that her husband and grown daughter care for her at home. She says she was too tired to eat much dinner that day. She is pleasant and slightly confused, although she can be reoriented. Her daughter, who accompanied her to the hospital, says this is her baseline state.

The patient’s complex home medication regimen includes glyburide, a first-generation sulfonylurea oral antidiabetic drug. On admission, she was switched to the fast-acting lispro, a sliding-scale insulin. Ted determines Mrs. Klein didn’t receive insulin coverage in the ED. As ordered, he performs preprandial and hour-of-sleep point-of-care (POC) BG checks.

Mrs. Klein declines a snack. At 10 pm, Ted sees her sleeping comfortably. An hour later, her daughter, who’s spending the night with her, tells him, “Something’s not right with Mom.”

On the scene

Ted finds Mrs. Klein hard to arouse, confused, and slurring her words. Her daughter tells him her mother slept most of the day, didn’t eat, and took “all of her meds,” including glyburide at home at 7 pm. On assessment, Ted finds the patient’s hands cold and clammy; her heart rate is 110 bpm. A fingerstick BG level reads 38 mg/dL. Per standing orders, Ted immediately administers 1 ampule of dextrose 50% I.V. and alerts her primary care provider. Mrs. Klein revives quickly. A POC BG check shows a level of 120 mg/dL.

Mrs. Klein is transferred to a step-down unit. Because patients who’ve taken sulfonylureas may experience refractory hypoglycemia, she’s placed on a protocol that includes hourly BG checks and I.V. fluid containing 5% dextrose.


In the step-down unit, Mrs. Klein is observed for 24 hours, where she has no further hypoglycemia signs or symptoms. Her primary care provider reevaluates her medications and decides to switch her from glyburide to a different oral antidiabetic class. 

Education and follow-up

Hypoglycemia is a serious and potentially lethal problem for all patients, particularly the frail elderly. Stay alert for factors that can cause hypoglycemia in these patients—sulfonylureas, polypharmacy, illness, declining kidney function, skipped meals, increased activity or exercise, and previous hypoglycemic events. After care transitions, take the time to understand the patient’s medication history, including the last time the patient ate and took medications.

Glyburide stimulates the pancreas to secrete insulin; in patients who skip a meal, it can cause hypoglycemia. Also, it stays in the body for up to 24 hours, prolonging hypoglycemia risk. The drug peaks at about 4 hours and in some cases can cause abrupt hypoglycemia onset. To anticipate and prevent hypoglycemia in patients on sulfonylureas, make sure you understand the onset, peak, and duration of these drugs. Given the hypoglycemia risk with oral antidiabetic drugs and insulin, many practitioners now deemphasize strict BG control in the frail elderly. Instead, they set patient-specific goals and focus on quality of life, including healthy eating.

Ted’s quick response to Mrs. Klein’s declining level of consciousness helped prevent a poor outcome. On discharge, he teaches Mrs. Klein and her family about hypoglycemia signs, symptoms, and treatment; the need to check her BG level regularly; and the importance of taking oral antidiabetic drugs with meals.

Dorothy Moore is an emergency department staff nurse at Kaiser Medical Center in Oakland, California and an adjunct lecturer at California State University in Hayward.

 Selected references

American Diabetes Association. Standards of medical care in diabetes—2015 abridged for primary care providers. Clin Diabetes. 2015;33(2):97-111.

Lee SJ, Eng C. Goals of glycemic control in frail older patients with diabetes. JAMA. 2011;305(13):1350–1.

Mayo Clinic Staff. Diseases and conditions: Diabetic hypoglycemica. (n.d.).

Rogers M, Sands C. Sulfonylurea-induced hypoglycemia: the case against glyburide. Consultant Live. February 7, 2011.

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