Insulin 70/30 Dose Calculation
For insulin-naive patients, start with 10 units daily or 0.1-0.2 units/kg/day, divided as 2/3 before breakfast and 1/3 before dinner; for patients converting from NPH insulin, calculate 80% of the current NPH total daily dose and split it the same way. 1
Initial Dosing for Insulin-Naive Patients
- Start with 10 units per day or 0.1-0.2 units/kg per day for patients beginning insulin therapy, as recommended by the American Diabetes Association 1
- Divide the total daily dose into 2/3 before breakfast and 1/3 before dinner 1, 2
- For example, if starting with 30 units total daily dose: give 20 units before breakfast and 10 units before dinner 1
Converting from NPH Insulin to 70/30
- Calculate 80% of the current NPH total daily dose (not 100%) to avoid hypoglycemia during transition 1, 2
- Distribute this reduced dose as 2/3 before breakfast and 1/3 before dinner 1, 2
- For example, if a patient takes 50 units NPH daily: calculate 50 × 0.8 = 40 units total, then give approximately 27 units before breakfast and 13 units before dinner 1, 2
Critical Pitfall to Avoid
Never convert on a 1:1 basis from NPH to 70/30 insulin, as this significantly increases hypoglycemia risk 1, 2. The American College of Endocrinology specifically warns against this common error 1.
Dose Titration Algorithm
- Monitor fasting plasma glucose (FPG) and set target of 90-150 mg/dL (4.0-7.0 mmol/L) 2, 3
- Increase the dose by 2 units every 3 days until reaching FPG goal without hypoglycemia 1
- If hypoglycemia occurs, determine the cause and reduce the corresponding dose by 10-20% if no clear reason is identified 1
- If A1C is <8% at baseline, consider lowering the calculated dose to avoid hypoglycemia during transition 1, 2
Monitoring Requirements During Transition
- Check blood glucose more frequently during the transition period, focusing on both fasting and postprandial levels 1, 2
- This is when hypoglycemia risk is highest, and neglecting monitoring is a common pitfall 1
- Target fasting glucose between 72-126 mg/dL (4.0-7.0 mmol/L) 2
- Research demonstrates that frequent clinic visits (biweekly) combined with sliding scale adjustments significantly improved glycemic control in patients using 70/30 insulin 4
Essential Clinical Considerations
- Consistent meal timing is particularly critical with premixed insulin regimens to avoid hypoglycemia 1, 2
- 70/30 insulin provides both basal and prandial coverage with fewer daily injections, simplifying the regimen compared to separate basal-bolus injections 1, 2
- The morning dose should typically be higher than the evening dose—never use the same dose for both injections 1, 2
- Clinical trial data shows that 70/30 insulin algorithms achieve superior glycemic control compared to traditional sliding scale insulin dosing in hospitalized patients 5
Practical Dosing Example
For a 70 kg patient starting insulin therapy: