What should be added to the current regimen of 4-20 units of lispro (insulin lispro) to control hyperglycemia in a patient with a glucose level of 300?

Add Basal Insulin Immediately

For a patient with glucose of 300 mg/dL on only sliding scale lispro (4-20 units), you must add basal insulin immediately—this is the single most critical intervention. 1

Why Basal Insulin is Essential

Your patient is on sliding scale insulin alone, which is explicitly condemned by all major diabetes guidelines and shown to be ineffective for glycemic control. 1 Sliding scale insulin only treats hyperglycemia reactively after it occurs rather than preventing it, leading to dangerous glucose fluctuations. 1 Randomized trials demonstrate that basal-bolus regimens provide superior glycemic control and reduce hospital complications compared to sliding scale insulin alone. 1

A glucose of 300 mg/dL with only correctional insulin indicates complete absence of basal coverage—the patient has no background insulin to suppress hepatic glucose production between meals and overnight. 1

Specific Basal Insulin Regimen

Start insulin glargine (Lantus) or detemir at 10 units once daily, administered at the same time each day. 1 For patients with severe hyperglycemia like this (glucose 300 mg/dL), consider a more aggressive starting dose of 0.3-0.4 units/kg/day. 1

Titrate the basal insulin aggressively: 1

• Increase by 4 units every 3 days if fasting glucose ≥180 mg/dL 1
• Increase by 2 units every 3 days if fasting glucose is 140-179 mg/dL 1
• Target fasting glucose: 80-130 mg/dL 1

Convert Sliding Scale to Scheduled Prandial Insulin

Discontinue sliding scale insulin as monotherapy immediately. 1 Instead, implement scheduled prandial insulin before meals:

• Start with 4 units of lispro before the largest meal, or use 10% of the basal dose 1
• Titrate prandial insulin by 1-2 units or 10-15% every 3 days based on 2-hour postprandial glucose readings 1
• Keep correction insulin (lispro) only as an adjunct for premeal glucose >250 mg/dL (add 2 units) or >350 mg/dL (add 4 units) 1

Foundation Therapy

Ensure the patient is on metformin unless contraindicated—it remains the foundation of type 2 diabetes therapy and should be continued when adding insulin. 1 Metformin reduces total insulin requirements and provides complementary glucose-lowering effects. 1

Critical Threshold to Monitor

When basal insulin exceeds 0.5 units/kg/day and approaches 1.0 units/kg/day, adding or intensifying prandial insulin becomes more appropriate than continuing to escalate basal insulin alone. 1 Signs of "overbasalization" include basal dose >0.5 units/kg/day, bedtime-to-morning glucose differential ≥50 mg/dL, hypoglycemia, and high glucose variability. 1

Common Pitfalls to Avoid

• Never continue sliding scale insulin as the sole treatment—this prolongs hyperglycemia exposure and increases complication risk 1
• Never delay basal insulin initiation—every day without basal coverage perpetuates dangerous glucose fluctuations 1
• Never rely solely on correction doses—scheduled basal-bolus therapy is superior to reactive sliding scale approaches 1
• Never discontinue metformin when starting insulin unless contraindicated, as this leads to higher insulin requirements and more weight gain 1

Monitoring Requirements

• Check fasting blood glucose every morning during titration 1
• Monitor 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
• If hypoglycemia occurs, reduce the corresponding dose by 10-20% immediately 1