How should I adjust the rapid‑acting insulin (NovoLog, insulin aspart) dosing for a sick type 2 diabetic patient who is on basal insulin (Lantus, insulin glargine) increased to 20 units nightly and sitagliptin (Januvia)?

NovoLog Dosing for Sick Type 2 Diabetic with Severe Hyperglycemia

Start NovoLog at 4 units before each meal (or 10% of the basal dose = 2 units per meal), and add correctional insulin using the "usual" column from the correction scale for blood sugars in the 400s range. 1

Structured Approach to Rapid-Acting Insulin Initiation

Starting Dose Calculation

Given your patient's situation with blood sugars in the 400s and Lantus now at 20 units:

• Scheduled prandial insulin: Start with 4 units of NovoLog before each meal (if eating regularly) 1
• Alternatively, use 10% of basal dose per meal = 2 units per meal 1
• Consider the higher dose (4 units) given the severe hyperglycemia (400s) 1

Correction (Supplemental) Insulin Protocol

For blood sugars in the 400s, add correction doses using the "usual" sensitivity column 2:

• BG 351-400 mg/dL: Add 14 units to scheduled dose
• BG ≥400 mg/dL: Add 16 units to scheduled dose 2

Important: These correction doses are added to the scheduled mealtime dose, not given instead of it 2.

Practical Prescription Example

NovoLog 100 units/mL:

• Inject 4 units subcutaneously before breakfast, lunch, and dinner
• Plus correction doses based on pre-meal blood glucose:
  • BG 141-180: add 4 units
  • BG 181-220: add 6 units
  • BG 221-260: add 8 units
  • BG 261-300: add 10 units
  • BG 301-350: add 12 units
  • BG 351-400: add 14 units
  • BG ≥400: add 16 units 2

Critical Considerations During Illness

Basal Insulin Adjustment

You may need to reduce the Lantus dose when adding prandial insulin. The 2017 ADA guidelines suggest decreasing basal insulin by the same amount as the starting mealtime dose 1. However, given the severe hyperglycemia (400s) during illness, maintain the 20 units of Lantus initially and reassess after 24-48 hours 2.

Januvia (Sitagliptin) Management

Continue the Januvia during this acute illness period 1. The guidelines indicate that DPP-4 inhibitors like Januvia can be continued when adding insulin therapy in outpatient settings 1. However, if the patient requires hospitalization, Januvia should be discontinued and replaced with scheduled insulin 2.

Monitoring and Titration

• Test blood glucose before each meal and at bedtime 3
• Daily dose adjustments are often necessary during illness 2
• If requiring >10-12 units of correction insulin in 24 hours, increase the scheduled prandial doses by that total amount, distributed across meals 2
• If fasting blood glucose remains elevated despite adequate basal insulin, increase Lantus by 2-4 units every 3 days 1, 4

Common Pitfalls to Avoid

Do NOT Use Sliding Scale Alone

Avoid using only correction insulin without scheduled doses 2. This approach leads to persistent hyperglycemia and increases the risk of complications 2. The evidence strongly supports scheduled basal-bolus regimens over sliding scale monotherapy 2.

Hypoglycemia Risk

• Start with the insulin-sensitive column if the patient has poor oral intake, is elderly, or has renal impairment 2
• Hold prandial insulin if the patient cannot eat, but continue basal insulin and correction doses every 4-6 hours 2
• Prescribe glucagon for emergency hypoglycemia 4

Sick Day Management

During illness, insulin requirements typically increase due to stress hormones and insulin resistance 3. The current severe hyperglycemia (400s) confirms this. Never stop basal insulin during illness 2.

Alternative Simplified Approach

If the full basal-bolus regimen seems too complex initially, consider a "basal-plus" strategy:

• Keep Lantus at 20 units nightly
• Add NovoLog 4 units before the largest meal only (typically dinner) 1, 5, 6
• Use correction insulin before other meals and bedtime 2, 7
• Add additional mealtime doses if blood sugars remain >180 mg/dL 1, 6

This stepwise intensification may improve adherence while achieving glycemic targets 5, 6, 8.