How is the dose of Insulin 70/30 (Novolin 70/30, NPH/Regular insulin) calculated for a patient?

Insulin 70/30 Calculation

The dose of Insulin 70/30 (Novolin 70/30, NPH/Regular insulin) should be calculated as 80% of the current NPH insulin total daily dose, divided into two daily injections with 2/3 given before breakfast and 1/3 given before dinner. 1

Initial Dosing Calculation

• For patients starting insulin therapy, begin with 10 units per day or 0.1-0.2 units/kg per day 2
• For patients converting from NPH insulin to 70/30 insulin, calculate the total daily dose as 80% of the current NPH total daily dose 1
• Divide the total daily dose into two injections: 2/3 before breakfast and 1/3 before dinner 1, 3

Example Calculation

• If a patient is currently taking 50 units of NPH insulin daily:
  • Calculate 80% of 50 units = 40 units total daily dose of 70/30 insulin 1
  • Morning dose (2/3 of total): 27 units (rounded)
  • Evening dose (1/3 of total): 13 units (rounded) 1, 3

Titration Process

• Monitor fasting plasma glucose (FPG) and set appropriate glycemic goals 2
• Choose an evidence-based titration algorithm, such as increasing by 2 units every 3 days until reaching FPG goal without hypoglycemia 2
• For hypoglycemia, determine the cause; if no clear reason is identified, lower the corresponding dose by 10-20% 2

Special Considerations

• More frequent blood glucose monitoring is essential during the transition period, focusing on both fasting and postprandial glucose levels 1
• Consistent meal timing is particularly important with premixed insulin regimens to avoid hypoglycemia 1, 3
• If A1C is <8%, consider lowering the calculated dose to avoid hypoglycemia during transition 1

Clinical Benefits of 70/30 Insulin

• Provides both basal and prandial coverage with fewer daily injections, simplifying the regimen compared to separate basal and bolus injections 1
• Studies have shown that 70/30 insulin algorithm is superior to traditional sliding scale insulin dosing for glycemic control in hospitalized patients 4
• Cost-effective option when compared to triple oral therapy or more complex insulin regimens 5

Common Pitfalls to Avoid

• Avoid converting on a 1:1 basis from NPH to 70/30 insulin 1
• Don't use the same dose for both morning and evening injections; the morning dose should typically be higher 3
• Never neglect monitoring during the transition period, as this is when hypoglycemia risk is highest 1
• Remember that meal timing becomes more critical with premixed insulins compared to basal-bolus regimens 1, 3