Initial Dosing for Insulin 70/30
For insulin 70/30 (NPH/Regular 70/30), start with 12 units before dinner or 0.1-0.2 units/kg/day divided into two doses (2/3 before breakfast, 1/3 before dinner) when transitioning from oral medications or adding to existing therapy. 1
Starting Dose Algorithms
Single Daily Injection Approach
- Begin with 12 units of 70/30 insulin before dinner (or 70-100% of prior basal insulin dose if converting from basal insulin) 2
- Alternatively, start with 10 units before dinner when transitioning from oral agents 3
- This once-daily approach is appropriate for patients with HbA1c 7.5-10% on oral medications 2, 3
Twice-Daily Regimen (Preferred for Most Patients)
- Total starting dose: 0.1-0.2 units/kg/day divided as 2/3 before breakfast and 1/3 before dinner 1
- For a 70 kg patient, this equals approximately 7-14 units total daily, split as 5-9 units before breakfast and 2-5 units before dinner 1
- When converting from bedtime NPH, use 80% of the current NPH dose, with 2/3 given before breakfast and 1/3 before dinner 1
Titration Protocol
Self-Titration Algorithm
- Increase dose by 2 units every 3 days to achieve fasting blood glucose target of 80-110 mg/dl 2, 3
- For the morning dose: titrate based on pre-dinner blood glucose 2
- For the evening dose: titrate based on pre-breakfast fasting blood glucose 2
- If hypoglycemia occurs without clear cause, reduce the corresponding dose by 10-20% 1
Expected Outcomes
- With once-daily 70/30 insulin, 21-41% of patients achieve HbA1c targets (<6.5% to <7%) 2
- With twice-daily 70/30 insulin, 52-70% achieve these targets 2
- Mean HbA1c reduction of 1.1-1.3% can be expected with once-daily dosing 3
- Greater reductions (2.8%) occur with twice-daily regimens 4
Clinical Context and Advantages
When to Use 70/30 Insulin
- Patients with HbA1c ≥8.5% benefit more from 70/30 insulin than basal-only insulin, achieving superior glycemic control 4
- 70/30 insulin is more effective than triple oral therapy, with comparable efficacy at lower cost ($3.20/day vs $10.40/day) 5
- Superior to sliding scale insulin for hospitalized patients, achieving better glycemic control with the same number of injections 6
Foundation Therapy
- Continue metformin (up to 2,550 mg/day) when initiating 70/30 insulin unless contraindicated 3, 4, 5
- Discontinue sulfonylureas to reduce hypoglycemia risk 3
Critical Thresholds and Advancement
When to Intensify Beyond Twice-Daily 70/30
- If HbA1c remains >6.5% after 16 weeks on twice-daily dosing, add a third pre-lunch injection starting at 3-6 units 2
- With three daily injections, 60-77% of patients achieve HbA1c targets 2
- Consider switching to basal-bolus therapy if 70/30 regimen fails to achieve targets after appropriate titration 1
Recognizing Overbasalization
- When total daily 70/30 insulin dose approaches 0.5 units/kg/day without achieving targets, consider transitioning to separate basal and prandial insulin for more precise control 1
- Clinical signals include persistent postprandial hyperglycemia despite adequate fasting glucose, hypoglycemia, and high glucose variability 1
Common Pitfalls to Avoid
- Do not use 70/30 insulin in hospitalized patients at high risk for hypoglycemia—basal-bolus regimens are safer 7
- Avoid premixed insulin in hospital settings due to unacceptably high hypoglycemia rates compared to basal-bolus therapy 7
- Do not delay insulin initiation—starting with 70/30 insulin is more effective than adding a third oral agent when two oral medications fail 5
- Ensure proper timing: 70/30 insulin must be given 30 minutes before meals (unlike rapid-acting analogs that can be given immediately before eating) 3
- Patient education on hypoglycemia recognition and treatment is essential before starting any insulin regimen 1