What is a substitute for Novolin 70/30 (insulin NPH and regular insulin)?

Substitute for Novolin 70/30

Humulin 70/30 is the most direct substitute for Novolin 70/30, as both are human insulin 70/30 NPH/Regular formulations with identical composition and pharmacokinetics, and Humulin 70/30 is typically the most cost-effective alternative. 1, 2

Direct Substitutes (Same Composition)

• Humulin 70/30 is the preferred substitute because it contains the identical 70% NPH and 30% Regular human insulin mixture as Novolin 70/30, allowing for straightforward conversion 1, 2
• When switching from Novolin 70/30 to Humulin 70/30, maintain the same total daily dose initially, but adjust the distribution to 2/3 before breakfast and 1/3 before dinner 1
• For example, if a patient takes 30 units in the morning and 20 units in the evening on Novolin 70/30, the equivalent Humulin 70/30 dosing would be approximately 33 units in the morning and 17 units in the evening 1

Alternative Premixed Insulin Analogs

If cost is not the primary concern and improved postprandial control is desired, consider these analog alternatives:

• NovoLog Mix 70/30 (Biphasic insulin aspart 70/30) contains 70% insulin aspart protamine and 30% soluble insulin aspart, providing earlier onset of action (10-20 minutes) compared to 30 minutes for Novolin 70/30 3, 4

• NovoLog Mix 70/30 demonstrates superior postprandial glucose control compared to human insulin 70/30, with mean time to peak activity of 2.4 hours versus 4.2 hours for Novolin 70/30 3, 4

• The safety profile of NovoLog Mix 70/30 is comparable to human insulin 70/30, with lower risk of major and nocturnal hypoglycemic events 5

• Humalog Mix 75/25 (Biphasic insulin lispro 25) is another analog option with 25% rapid-acting lispro and 75% protaminated lispro 4, 5

Conversion Algorithm

Step 1 - Choose the substitute based on clinical priorities:

• If cost is the primary concern → Humulin 70/30 (human insulin formulations are typically less expensive than analogs) 6, 2
• If postprandial glucose control is inadequate → NovoLog Mix 70/30 or Humalog Mix 75/25 2, 4
• If patient prefers fewer injections and has consistent meal timing → any premixed formulation is appropriate 2

Step 2 - Adjust dosing distribution:

• Never convert on a 1:1 basis without adjusting the morning/evening distribution 1, 2
• Use 2/3 of total daily dose before breakfast and 1/3 before dinner 1
• The morning dose should always be higher than the evening dose 1, 2

Step 3 - Implement intensive monitoring:

• Increase blood glucose monitoring frequency during the transition period, checking both fasting and postprandial levels 1, 2
• Target fasting glucose 72-126 mg/dL (4.0-7.0 mmol/L) 2
• Monitor for hypoglycemia, which is the highest risk during the transition period 1, 2

Critical Considerations During Transition

• Meal timing becomes more critical with premixed insulins compared to basal-bolus regimens, as the fixed ratio of short and intermediate-acting insulin requires consistent carbohydrate intake 2, 7
• Continue metformin when starting or switching premixed insulin 2
• Discontinue sulfonylureas, DPP-4 inhibitors, and GLP-1 agonists when using premixed insulin regimens to avoid overlapping mechanisms and hypoglycemia risk 2

Common Pitfalls to Avoid

• Never use the same dose for both morning and evening injections - this is the most common dosing error 1, 2
• Avoid administering premixed insulin at the same time as basal insulin if the patient is on both, as this creates insulin stacking and severe hypoglycemia risk 7
• Don't neglect patient education about the critical importance of consistent meal timing to prevent hypoglycemia 1, 2
• If hypoglycemia occurs during transition, reduce the dose by 2 units and reassess 7

Cost Considerations

• Human insulin formulations (Novolin 70/30, Humulin 70/30) can be purchased for considerably less than analog premixed insulins at select pharmacies 6
• For patients with cost concerns, relaxed A1C goals, or prominent insulin resistance, human insulin 70/30 formulations are the appropriate choice 6, 2
• The American Diabetes Association emphasizes that clinicians should be familiar with human insulin use given cost considerations 6