What is the recommended dosing and administration protocol for Sliding Scale Insulin (SSI) regular insulin for managing hyperglycemia?

Sliding Scale Insulin (SSI) Regular Insulin: Not Recommended as Sole Therapy

Sliding scale insulin should be strongly discouraged as the sole method of insulin treatment in hospitalized patients, and basal-bolus insulin regimens should be used instead for better glycemic control and reduced complications. 1

Why SSI Alone is Inadequate

The evidence consistently demonstrates that SSI as monotherapy results in:

• Worse glycemic control compared to basal-bolus regimens, with mean blood glucose levels approximately 14.8 mg/dL (0.8 mmol/L) higher 2
• Higher treatment failure rates of 19% with SSI versus 0-2% with basal-bolus or basal-plus regimens 1
• Increased postoperative complications (24% vs 9%; p=0.003) when compared to structured insulin regimens 1
• Reactive rather than proactive glucose management, treating hyperglycemia after it occurs rather than preventing it 1

When SSI Regular Insulin May Be Used

SSI should only be considered in very limited circumstances 1:

• Short-term acute illness with irregular dietary intake, transitioning back to scheduled insulin once stabilized 1
• As correction doses (not sole therapy) added to scheduled basal-bolus insulin regimens 1
• Wide glucose fluctuations in patients with cognitive decline and chronically irregular intake, using simplified scales (e.g., "give 4 units if glucose >300 mg/dL") 1

Recommended SSI Regular Insulin Dosing Protocol (When Used as Correction)

For non-DKA hyperglycemia in hospitalized adults who are NPO 3:

• Administer subcutaneously every 6 hours 3
• Give 5-unit increments for every 50 mg/dL increase above 150 mg/dL 3
• Maximum single dose: 20 units for blood glucose of 300 mg/dL 3

Alternative rapid-acting insulin analogs can be given every 4 hours instead of regular insulin every 6 hours 3

Pharmacokinetics of Regular Insulin

Understanding regular insulin's action profile is critical 3:

• Onset: 15 minutes to 1.2 hours
• Peak effect: 3-4 hours (range 2-5.7 hours)
• Duration: 6-8 hours (some effects up to 16 hours)

Preferred Alternative: Basal-Bolus Regimens

The recommended approach for hospitalized patients with good nutritional intake 1:

• Basal insulin (glargine, detemir, or NPH) to provide background coverage
• Nutritional/prandial insulin (regular or rapid-acting) with meals
• Correction insulin for hyperglycemia above target

For patients with poor oral intake or NPO 1:

• Basal insulin plus correction insulin regimen is preferred over SSI alone

Transitioning Away from SSI in Long-Term Care

If SSI is the sole insulin therapy 1:

1. Review average daily insulin requirement over prior 5-7 days
2. Give 50-75% of average daily requirement as basal insulin
3. Stop SSI completely
4. Use noninsulin agents or fixed-dose mealtime insulin for postprandial hyperglycemia
5. Consider morning basal insulin dosing to reduce early-morning hypoglycemia risk

If SSI is used with scheduled basal insulin 1:

• Add 50-75% of average SSI requirement to existing basal insulin dose
• Discontinue reactive SSI approach

Glycemic Targets

For most non-critically ill hospitalized patients 1:

• Premeal glucose: <140 mg/dL (7.8 mmol/L)
• Random glucose: <180 mg/dL (10.0 mmol/L)
• Reassess regimen if glucose falls below 100 mg/dL (5.6 mmol/L)
• Modify regimen immediately if glucose <70 mg/dL (3.9 mmol/L) 1

Critical Pitfalls to Avoid

Never use SSI as monotherapy in hospitalized patients—it consistently underperforms structured insulin regimens 1, 2

Avoid the "reactive trap": SSI treats hyperglycemia after it occurs rather than preventing it, leading to prolonged periods of poor control 1

Don't ignore hypoglycemia risk: While basal-bolus regimens may have higher hypoglycemia rates (23% vs 5%), they achieve significantly better overall glycemic control and reduced complications 1

Inadequate communication: SSI orders are frequently miscommunicated during transitions of care, leading to medication errors 1

Special Populations

Patients on enteral or parenteral nutrition 3:

• Regular insulin every 6 hours OR rapid-acting every 4 hours
• Must be part of structured regimen, not SSI alone

Surgical patients 1:

• Basal-bolus regimens reduce complications by 15% absolute risk reduction despite higher hypoglycemia rates
• SSI alone results in worse outcomes