Should I give glipizide to an NPO patient with a blood glucose of 112?

Do Not Give Glipizide to This NPO Patient

You should hold the glipizide for this NPO patient with a blood glucose of 112 mg/dL. 1 Sulfonylureas like glipizide stimulate insulin secretion regardless of food intake, creating significant hypoglycemia risk when patients cannot eat. 2, 3

Why Glipizide Must Be Held in NPO Patients

• Glipizide causes insulin secretion independent of glucose levels and food intake, making hypoglycemia inevitable when the patient cannot consume carbohydrates to match the drug-induced insulin release. 1, 4
• The FDA label explicitly states glipizide should be given approximately 30 minutes before a meal to achieve glucose reduction, implying it should not be given without planned food intake. 1
• Perioperative guidelines recommend withholding oral hypoglycemic agents the morning of surgery or procedures when patients are NPO. 2

Specific Risks in This Clinical Scenario

• Blood glucose of 112 mg/dL provides minimal buffer before reaching the hypoglycemia threshold of <70 mg/dL, especially concerning given glipizide's peak effect occurs 1.8-2.3 hours after administration. 5
• Glipizide has a 4-5 hour elimination half-life, meaning its hypoglycemic effect persists well beyond a single missed meal, with maximal glucose-lowering maintained between 1.5-8 hours despite falling drug levels. 5
• Sulfonylureas are the oral agents with highest hypoglycemia risk, second only to insulin among all diabetes medications. 6

What to Do Instead

• Monitor blood glucose every 4-6 hours minimum while NPO, increasing to every 1-2 hours if glucose trends downward toward 100 mg/dL or below. 2, 3
• Hold all sulfonylureas until the patient resumes oral intake and can consume adequate calories to match the medication's insulin-stimulating effect. 2
• If blood glucose rises above 180 mg/dL while NPO, use short-acting (regular) insulin every 6 hours or rapid-acting insulin every 4 hours for correction rather than restarting glipizide. 2
• Provide IV dextrose (D5W) if any insulin is required to prevent hypoglycemia in the NPO state, targeting glucose 100-150 mg/dL. 3

Critical Pitfalls to Avoid

• Never use sliding-scale sulfonylureas or give scheduled sulfonylureas to NPO patients—this practice is dangerous and strongly discouraged. 2, 6
• Do not assume a "normal" glucose of 112 mg/dL means the medication is safe—glipizide will drive glucose down regardless of starting value when no carbohydrates are consumed. 1, 4
• Avoid restarting glipizide immediately when NPO status ends—ensure the patient can tolerate and will consume a full meal before giving the dose 30 minutes prior. 1

When to Resume Glipizide

• Restart glipizide only when the patient has resumed full oral intake and can consume meals of adequate caloric content. 1
• Give the dose approximately 30 minutes before the meal as specified in the FDA labeling to optimize postprandial glucose control. 1
• Consider reducing the dose initially (especially in elderly, debilitated, or malnourished patients) to avoid hypoglycemia after a period of fasting and potential illness. 1