What adjustments should be made to a patient's current insulin regimen, who is already on a sliding scale with lispro (humalog), to achieve optimal glucose control?

Transitioning from Sliding Scale Lispro to a Scheduled Basal-Bolus Insulin Regimen

Sliding scale insulin as monotherapy must be immediately discontinued and replaced with a scheduled basal-bolus regimen, as sliding scale monotherapy is explicitly condemned by all major diabetes guidelines and shown to be ineffective. 1

Critical Problems with Current Sliding Scale-Only Approach

• Sliding scale insulin treats hyperglycemia reactively after it occurs rather than preventing it, leading to dangerous glucose fluctuations and poor glycemic control. 1
• Scheduled basal-bolus regimens are superior to sliding scale monotherapy, with 68% of patients achieving mean blood glucose <140 mg/dL versus only 38% with sliding scale alone. 1
• All patients requiring insulin should be on a scheduled regimen with basal, prandial, and correction components—not correction insulin alone. 1

Recommended Insulin Regimen Structure

Add Basal Insulin Immediately

• Start basal insulin (insulin glargine or detemir) at 10 units once daily OR 0.1-0.2 units/kg body weight, administered at the same time each day. 1
• For patients with severe hyperglycemia (HbA1c ≥9%, blood glucose ≥300-350 mg/dL), consider higher starting doses of 0.3-0.5 units/kg/day as total daily insulin dose. 1
• The basal insulin provides 24-hour background insulin coverage to control fasting and between-meal glucose levels. 1

Convert Sliding Scale Lispro to Scheduled Prandial Insulin

• Continue lispro but administer it as scheduled prandial insulin before each meal (within 15 minutes before or immediately after meals), not as sliding scale only. 2
• Start with 4 units of lispro before each meal, OR use 10% of the basal insulin dose per meal. 1
• The total daily insulin dose is typically split 50% as basal insulin and 50% as prandial insulin divided among three meals. 1, 2

Retain Correction Doses as Adjunct Only

• Use a simplified correction scale with lispro: add 2 units for premeal glucose >250 mg/dL and 4 units for premeal glucose >350 mg/dL, but only as an adjunct to scheduled basal and prandial insulin. 1
• Correction insulin addresses acute hyperglycemic excursions but does not replace scheduled insulin therapy. 1

Basal Insulin Titration Algorithm

• Increase basal insulin by 2 units every 3 days if fasting glucose is 140-179 mg/dL. 1
• Increase basal insulin by 4 units every 3 days if fasting glucose is ≥180 mg/dL. 1
• Target fasting plasma glucose: 80-130 mg/dL. 1
• If hypoglycemia occurs without clear cause, reduce the dose by 10-20% immediately. 1

Prandial Insulin Titration

• Titrate prandial lispro by 1-2 units or 10-15% every 3 days based on 2-hour postprandial glucose readings. 1
• Target postprandial glucose <180 mg/dL. 1
• Adjust each meal's insulin dose independently based on the postprandial glucose after that specific meal. 1

Critical Threshold: Recognizing Overbasalization

• When basal insulin exceeds 0.5 units/kg/day and approaches 1.0 units/kg/day, focus on intensifying prandial insulin rather than continuing to escalate basal insulin alone. 1
• Clinical signals of overbasalization include: basal dose >0.5 units/kg/day, bedtime-to-morning glucose differential ≥50 mg/dL, hypoglycemia, and high glucose variability. 1

Foundation Therapy

• Continue metformin (unless contraindicated) at maximum tolerated dose (up to 2000-2500 mg daily) when adding or intensifying insulin therapy. 1
• Metformin provides superior glycemic control with reduced insulin requirements and less weight gain compared to insulin alone. 1

Monitoring Requirements

• Daily fasting blood glucose monitoring is essential during titration. 1
• Check pre-meal and 2-hour postprandial glucose to guide prandial insulin adjustments. 1
• Reassess every 3 days during active titration and every 3-6 months once stable. 1

Common Pitfalls to Avoid

• Never continue sliding scale insulin as monotherapy—this approach is ineffective and dangerous. 1
• Do not delay adding scheduled basal insulin when transitioning from sliding scale. 1
• Avoid "stacking" correction doses by giving insulin too frequently; insulin from the previous dose may still be active. 1
• Do not continue escalating basal insulin beyond 0.5-1.0 units/kg/day without addressing postprandial hyperglycemia with adequate prandial coverage. 1

Patient Education Essentials

• Teach proper insulin injection technique and site rotation within the same region (abdomen, thigh, upper arm, or buttocks) to reduce lipodystrophy risk. 2
• Educate on recognition and treatment of hypoglycemia: treat with 15 grams of fast-acting carbohydrate when blood glucose ≤70 mg/dL. 1
• Provide instruction on self-monitoring of blood glucose, "sick day" management rules, and insulin storage and handling. 1