Sulfonylureas with Insulin – Case Scenario

One of my biggest pet peeves is the use of sulfonylureas with insulin. Recall that sulfonylureas stimulate the release of insulin and in many patients with Type 2 diabetes we may not be getting much out of the sulfonylurea or in some cases, the extra boost in insulin release from the body may be contributing to blood sugar variability, and the risk for hypoglycemia. In this case scenario, I’ll describe a situation where it would be obvious to avoid sulfonylureas with insulin.

RH is a 78-year-old male with a 15-year history of type 2 diabetes, along with hypertension and mild cognitive impairment. He presents to the clinic accompanied by his daughter, who reports that he has had several recent episodes of morning dizziness and near-falls. Home blood glucose monitoring reveals fasting levels consistently in the 70–90 mg/dL range over the past week, with one reading as low as 62 mg/dL. His daughter notes that he often eats inconsistently in the morning and sometimes skips breakfast altogether. His most recent hemoglobin A1c is 5.9%, indicating tight glycemic control.

Current Medications:

Insulin glargine 30 units at bedtime
Insulin lispro 5 units with meals (TID)
Glipizide 2.5 mg daily
Lisinopril 10 mg daily
Atorvastatin 20 mg nightly

Given RH’s age, cognitive decline, and the use of both basal-bolus insulin and a sulfonylurea, he is at increased risk for hypoglycemia. The low-dose glipizide adds little benefit in the context of intensive insulin therapy and is likely contributing to the episodes of low blood sugar. Given the lower A1C, discontinuing the glipizide to minimize hypoglycemia risk would be appropriate. Additional counseling should include caregiver education on recognizing and managing low blood sugar and close follow-up with glucose monitoring after stopping the sulfonylurea. In the future, simplification of the insulin regimen may also be warranted if his functional status declines further. Cognitive status and the use of insulin should routinely be monitored to ensure that this patient is safely using therapy.

Whenever you see the use of sulfonylureas with insulin, please be sure to assess if this regimen is appropriate. Many times we can simplify the regimen by discontinuing the sulfonylurea.

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