How should Lantus (insulin glargine) be managed in a patient with diabetes who is not eating?

Managing Lantus (Insulin Glargine) in Patients Who Are Not Eating

Continue basal insulin (Lantus) at a reduced dose even when patients are not eating, as basal insulin is essential to prevent diabetic ketoacidosis (DKA) in type 1 diabetes and to avoid dangerous hyperglycemia in type 2 diabetes. 1

Critical Principle: Basal Insulin Must Continue

Basal insulin should be administered to avoid DKA even when patients are unable to ingest meals. 1 This is particularly crucial for:

• Type 1 diabetes patients: Require continuous basal insulin coverage to prevent ketoacidosis, regardless of oral intake 1
• Type 2 diabetes patients: Need basal insulin to control fasting glucose and suppress hepatic glucose production between meals 1

The fundamental concept is that basal insulin addresses background insulin needs—not meal coverage—and these needs persist even during fasting states.

Dose Reduction Strategy for NPO/Poor Oral Intake

When patients have decreased or absent oral intake, reduce the total daily insulin dose but continue basal insulin coverage rather than discontinuing it entirely. 1

Specific Dosing Recommendations:

• High-risk patients (elderly >65 years, renal failure, poor oral intake): Use lower doses of 0.1-0.25 units/kg/day 2
• Hospitalized patients with reduced oral intake: Start with 0.1-0.15 units/kg/day given primarily as basal insulin 2
• Patients on high-dose home insulin (≥0.6 units/kg/day): Reduce total daily dose by 20% upon hospitalization or when oral intake decreases 2
• Advanced type 1 diabetes with organ failure: Continue reduced but continued insulin dosing as oral food intake decreases 1

For Patients on Enteral/Parenteral Nutrition:

Basal insulin needs are typically 30-50% of total daily insulin requirement for patients on tube feeding or parenteral nutrition. 2 A reasonable starting point is 10 units of insulin glargine every 24 hours for patients requiring insulin on artificial nutrition. 2, 3

Monitoring Requirements

Check glucose every 4-6 hours for patients with poor oral intake, rather than the standard pre-meal testing. 1, 4 This allows for:

• Early detection of hypoglycemia
• Appropriate use of correction insulin for hyperglycemia >180 mg/dL
• Timely dose adjustments based on glucose patterns

Correction Insulin as Adjunct

While basal insulin continues at reduced doses, use correction doses of rapid-acting insulin only for significant hyperglycemia (typically >180-250 mg/dL). 4 However, never rely solely on sliding scale insulin without basal coverage—this approach is explicitly condemned by guidelines and leads to dangerous glucose fluctuations. 1, 4

A simplified correction scale may include:

• 2 units of rapid-acting insulin for glucose >250 mg/dL
• 4 units for glucose >350 mg/dL 2

Common Pitfalls to Avoid

Do not completely discontinue basal insulin when patients stop eating. 1, 4 This dangerous practice leads to:

• Diabetic ketoacidosis in type 1 diabetes patients 1
• Severe hyperglycemia and metabolic derangement in type 2 diabetes 4
• Worsening glycemic control requiring more aggressive intervention later 4

Do not use sliding scale insulin alone without basal coverage. 1, 4 Randomized trials demonstrate that basal-bolus regimens provide superior glycemic control and reduce hospital complications compared to sliding scale monotherapy. 4

Do not forget to reduce prandial insulin doses when oral intake decreases—while basal insulin continues at reduced doses, prandial insulin should be held or dramatically reduced when patients are not eating. 1

Special Considerations

Illness and Stress States:

Insulin requirements may be altered during intercurrent conditions such as illness, emotional disturbances, or other stresses. 5 Some patients may actually require increased basal insulin during acute illness despite poor oral intake, due to counter-regulatory hormone responses.

Hypoglycemia Prevention:

If hypoglycemia occurs, reduce the basal insulin dose by 10-20% immediately. 2 The risk of hypoglycemia increases significantly in patients with:

• Renal impairment (requiring 35-50% dose reduction in advanced CKD) 2
• Hepatic impairment 5
• Elderly patients 2
• Those with unpredictable oral intake 1

Transition Planning:

When oral intake resumes, gradually increase insulin doses back toward baseline requirements based on glucose monitoring and carbohydrate intake. 1 Ensure proper coordination between resumption of meals and restoration of prandial insulin coverage.