How should insulin be administered to a hospitalized patient after oral hypoglycemic agents (OHA) have been discontinued?

Insulin Administration After Stopping Oral Hypoglycemic Agents in Hospitalized Patients

Discontinue all oral hypoglycemic agents immediately upon hospital admission and transition to a scheduled subcutaneous basal-bolus insulin regimen, not sliding scale insulin alone. 1

Why Discontinue Oral Agents?

Oral hypoglycemic agents should be stopped at hospital admission because:

• Contraindications are present in a high percentage of hospitalized patients (renal dysfunction, hepatic impairment, hemodynamic instability, NPO status)
• Oral agents delay achievement of glycemic targets
• Metformin risks lactic acidosis with contrast dye, surgery, or acute illness
• Thiazolidinediones take weeks for full effect and are contraindicated in heart failure
• DPP-4 inhibitors are less useful when patients aren't eating 1

Critical pitfall: Using sliding scale insulin (SSI) alone after stopping oral agents increases the risk of hyperglycemia 3-fold and causes undesirable hypoglycemia. SSI is strongly discouraged. 1, 2

Calculate Starting Insulin Dose

Use weight-based dosing for the total daily dose (TDD) 1:

For patients ≥70 years OR GFR <60 mL/min:

• Start at 0.2-0.3 units/kg/day

For other patients with blood glucose 140-200 mg/dL:

• Start at 0.4 units/kg/day

For blood glucose 201-400 mg/dL:

• Start at 0.5 units/kg/day

Distribute the Insulin Dose

Split the total daily dose as 50% basal and 50% nutritional (bolus) insulin 1:

Basal Insulin Component:

• Give glargine or detemir once daily (or detemir/NPH twice daily)
• Administer at the same time each day
• Continue basal insulin even if patient is NPO

Nutritional (Bolus) Insulin Component:

If patient is eating:

• Divide the nutritional portion into three equal doses before each meal
• Use rapid-acting insulin (lispro, aspart, glulisine)
• Hold prandial insulin if patient cannot eat 1, 2

If patient is NPO or not eating:

• Give basal insulin alone
• Add correction doses with rapid-acting insulin every 4 hours OR regular insulin every 6 hours 1

Add Correction (Supplemental) Insulin

Always add correction insulin on top of scheduled doses using a standardized scale 1:

Standard correction scale (use "Usual" column for most patients):

• BG 141-180 mg/dL: add 4 units
• BG 181-220 mg/dL: add 6 units
• BG 221-260 mg/dL: add 8 units
• BG 261-300 mg/dL: add 10 units
• BG 301-350 mg/dL: add 12 units
• BG 351-400 mg/dL: add 14 units
• BG ≥400 mg/dL: add 16 units

Use "Insulin-sensitive" column (lower doses) for:

• Elderly patients
• Patients not eating
• Impaired renal function

Use "Insulin-resistant" column (higher doses) for:

• Patients on corticosteroids
• Those previously requiring >80 units/day 1

Special Considerations

For patients already on home insulin:

• Reduce home total daily dose by 20% on admission if poor nutrition, renal impairment, or admission glucose <100 mg/dL 1
• Do NOT continue home dose unchanged—this increases hypoglycemia risk 1

For Type 1 diabetes patients:

• MUST receive continuous basal insulin even when NPO to prevent diabetic ketoacidosis
• Never stop basal insulin completely 1, 3

Transitioning from IV insulin:

• Give subcutaneous basal insulin 1-2 hours BEFORE stopping IV insulin
• Convert at 60-80% of the 24-hour IV insulin dose 2

Daily Adjustments

Adjust insulin doses daily based on point-of-care glucose monitoring:

• If correction insulin needed before most meals → increase basal insulin
• If glucose elevated at one specific time → increase the preceding bolus dose
• Monitor for hypoglycemia and reduce doses accordingly 1

Target glucose range: 140-180 mg/dL for most hospitalized patients 2

This basal-bolus approach with scheduled insulin is safe, efficacious, and superior to sliding scale insulin alone, achieving better glycemic control with lower rates of complications. 1, 4, 5