Can Novamix (biphasic insulin aspart) and Protaphane (neutral protamine Hagedorn insulin, NPH insulin) be given together?

Can Novamix and Protaphane Be Given Together?

No, Novamix (biphasic insulin aspart) and Protaphane (NPH insulin) should not be mixed together in the same syringe, as Novamix is already a premixed formulation containing both rapid-acting insulin aspart and protamine-crystallized insulin aspart, making additional mixing with NPH unnecessary and potentially problematic.

Why These Insulins Should Not Be Combined

Novamix Is Already a Complete Premixed Formulation

• Novamix contains 30% soluble insulin aspart and 70% protamine-crystallized insulin aspart, designed to address both prandial and basal insulin needs with a single product 1
• This premixed formulation is specifically engineered to provide both rapid-acting coverage for meals and intermediate-acting basal coverage 1
• Adding additional NPH (Protaphane) would create an unpredictable insulin profile with excessive intermediate-acting insulin 2

Protamine-Based Insulins Should Not Be Mixed With Other Protamine Formulations

• Both Novamix and Protaphane contain protamine, and mixing two protamine-based formulations creates unpredictable pharmacokinetics 3
• The American Diabetes Association specifically states that phosphate-buffered insulins like NPH should not be mixed with other protamine-containing preparations due to precipitation concerns 2, 3

Appropriate Use of These Insulins

If Using Novamix (Biphasic Insulin Aspart)

• Administer Novamix twice daily, typically before breakfast and dinner, injecting within 15 minutes before meals 4, 1
• Novamix provides superior postprandial glucose control compared to traditional biphasic human insulin (BHI 30) 1
• This regimen alone can achieve HbA1c targets <7.0% in many patients with type 2 diabetes 1

If Using Protaphane (NPH) With Rapid-Acting Insulin

• NPH can be mixed with rapid-acting insulin aspart (NovoRapid/NovoLog) in the same syringe 2, 3
• When rapid-acting insulin is mixed with NPH, inject within 15 minutes before a meal 2, 3
• This mixture maintains the pharmacokinetic profile of rapid-acting insulin with only slight decrease in absorption rate but no reduction in total bioavailability 3
• The mixture can be used immediately or stored for future use 2, 3

Clinical Decision Algorithm

Choose one regimen, not both:

1. For patients needing twice-daily premixed insulin: Use Novamix alone (no additional NPH needed) 1

2. For patients needing flexible basal-bolus therapy: Use NPH (Protaphane) as basal insulin mixed with rapid-acting insulin aspart before meals 2, 3, 5

3. For patients on basal-bolus requiring intensification: Consider switching from NPH + rapid-acting insulin to Novamix twice daily, or advance to full basal-bolus with multiple rapid-acting injections 2

Critical Pitfall to Avoid

• Never attempt to "customize" a premixed insulin like Novamix by adding additional basal insulin (NPH), as this destroys the carefully engineered 30/70 ratio and creates unpredictable insulin action 2, 3
• Visual inspection before use should reveal Novamix as uniformly cloudy; any clumping, frosting, or precipitation indicates loss of potency 2, 4