Insulin Regimen Adjustment for Persistent Hyperglycemia
Increase the Lantus (basal insulin) dose immediately to 20-25 units once daily and titrate upward by 2-4 units every 3-4 days until fasting blood glucose reaches 100-130 mg/dL, while continuing to adjust the Humalog 75/25 based on pre-meal and bedtime glucose patterns. 1
Critical Problem with Current Regimen
Your patient's regimen reveals a fundamental imbalance:
The basal insulin dose is grossly inadequate. Only 16 units of Lantus provides insufficient 24-hour basal coverage for most patients with type 2 diabetes, who typically require 0.3-0.5 units/kg/day of basal insulin alone 1
Total daily insulin is likely insufficient. Patients with type 2 diabetes often need approximately 1 unit/kg/day total insulin, with roughly 50% as basal insulin—this patient is receiving far less than this target 1
The premixed insulin (Humalog 75/25) cannot compensate for inadequate basal coverage, as it provides only 6-8 hours of intermediate-acting insulin per dose, leaving gaps in basal coverage 2
Immediate Adjustment Strategy
Step 1: Optimize Basal Insulin First
Increase Lantus from 16 to 20-25 units administered once daily at the same time each evening 1
Titrate aggressively using a structured algorithm: Add 2-4 units every 3-4 days until fasting blood glucose consistently reaches 100-130 mg/dL 1, 3
Continue titration even if doses exceed 0.5 units/kg/day, as inadequate basal insulin is the primary driver of persistent hyperglycemia in this case 2
Step 2: Reassess the Premixed Insulin Component
Once basal insulin is optimized (fasting glucose 100-130 mg/dL):
If blood glucose remains elevated throughout the day (in the 200s), the Humalog 75/25 dose needs adjustment based on pre-meal glucose patterns 1
Consider whether the 75/25 formulation is appropriate. The 75/25 mix provides 25% rapid-acting lispro and 75% intermediate-acting insulin. If evening/overnight glucose is controlled but daytime glucose remains high, switching to 50/50 mix at breakfast and lunch may provide more prandial coverage 2, 4
Distribute mealtime insulin based on carbohydrate intake, typically 30-40% at each meal, adjusting the premixed doses accordingly 1
Monitoring During Adjustment
Check blood glucose before each meal and at bedtime daily during the titration period to identify patterns of hyperglycemia or hypoglycemia 1
Focus on fasting glucose first. Once fasting glucose reaches target (100-130 mg/dL), shift attention to post-meal glucose control 1
Watch for hypoglycemia. If blood glucose drops below 70 mg/dL, reduce the most recent insulin increase by 2-4 units 3
Alternative Regimen Consideration
If glucose control remains inadequate despite optimizing both insulins:
Consider transitioning to a basal-bolus regimen (Lantus once daily plus rapid-acting insulin lispro before each meal) rather than continuing premixed insulin 2
This approach offers greater flexibility and may achieve better glycemic control, though it requires more injections 2, 5
Alternatively, add a GLP-1 receptor agonist to the regimen to improve postprandial control and potentially reduce total insulin requirements 1, 2
Critical Pitfalls to Avoid
Do not assume the current total insulin dose is adequate. The persistent hyperglycemia in the 200s indicates significant insulin deficiency 1
Do not adjust both basal and prandial insulin simultaneously during initial titration—optimize basal insulin first, then address prandial coverage 1, 3
Do not use premixed insulin if the patient has irregular meal patterns, as these formulations require consistent meal timing 2
Ensure the patient is not mixing insulin glargine with other insulins, as this is contraindicated due to its low pH diluent 2
Adjunctive Therapy
Confirm metformin is prescribed (if not contraindicated) to improve insulin sensitivity and reduce insulin requirements 2, 1
Consider adding an SGLT-2 inhibitor in patients requiring large insulin doses, as this can improve control and reduce insulin needs, though potential side effects must be weighed 2