What is a suitable substitute for 70/30 (seventy/thirty) insulin?

Suitable Substitutes for 70/30 Insulin

Several suitable substitutes for 70/30 insulin include 70/30 aspart mix, 75/25 or 50/50 lispro mix, and 70/30 degludec/aspart mix, with analog formulations generally providing better postprandial control than NPH/regular 70/30 insulin.

Premixed Insulin Options

Direct Substitutes

• 70/30 aspart mix (NovoLog Mix 70/30): Contains 70% protamine-crystallized aspart and 30% soluble aspart 1
• 75/25 lispro mix (Humalog Mix 75/25): Contains 75% protamine-crystallized lispro and 25% soluble lispro 1
• 50/50 lispro mix (Humalog Mix 50/50): Contains 50% protamine-crystallized lispro and 50% soluble lispro 1
• 70/30 degludec/aspart mix: Once or twice-daily administration before meals 1
• 70/30 NPH/regular insulin mix: Less costly alternative but suboptimal pharmacodynamic profile 1

Considerations for Selection

• Analog formulations (aspart, lispro) have more physiological pharmacokinetic profiles than human insulin premixes 2
• Postprandial glycemic control is better with premixed insulin analogs than with premixed human insulin 2
• Timing flexibility: Premixed analogs allow more flexible injection timing relative to meals, improving adherence and quality of life 2

Alternative Insulin Regimens

If switching from 70/30 insulin to a different regimen is desired, consider:

Basal-Bolus Regimen

• Basal insulin (glargine, detemir, degludec) plus rapid-acting insulin (lispro, aspart, glulisine) before meals 1
• Offers greater flexibility for patients with irregular meal schedules 1
• Starting dose for prandial insulin: 4 units or 10% of basal dose before largest meal 1

Basal Insulin Plus GLP-1 RA

• Combination of basal insulin with GLP-1 receptor agonist 1
• Less weight gain and hypoglycemia compared to intensified insulin regimens 1
• Available as fixed-ratio combinations (insulin glargine/lixisenatide or insulin degludec/liraglutide) 1

Dosing and Administration

Initial Dosing

• For premixed insulin: Administer twice daily, typically before breakfast and dinner 1, 3
• Initial dose can be based on previous insulin requirements or started at 10 units twice daily 3

Timing Considerations

• Premixed analog insulins: Can be administered immediately before meals (within 5-10 minutes) 4
• Premixed human insulin: Should be administered 30 minutes before meals 4
• Some elderly patients may benefit from postprandial dosing (15-20 minutes after meal onset) with biphasic insulin aspart 4

Advantages of Analog Premixed Formulations

• Faster onset and shorter duration of action compared to regular human insulin 5
• Lower risk of hypoglycemia, particularly nocturnal events 5, 6
• Greater convenience with more flexible timing relative to meals 2, 6
• Improved adherence due to simplified regimen compared to basal-bolus therapy 2

Clinical Considerations

Efficacy

• All premixed insulin formulations can effectively reduce HbA1c by 1.1-1.3% when transitioning from oral agents 7
• Patients achieving fasting plasma glucose <126 mg/dL experience the largest decreases in HbA1c (1.8-2.3%) 7

Special Populations

• For elderly patients, premixed analog insulins may be preferred due to lower hypoglycemia risk and flexible dosing 4
• For patients with irregular meal patterns, basal-bolus regimens may be more appropriate than premixed insulins 1

Monitoring and Adjustment

• Adjust premixed insulin doses based on pre-meal and bedtime glucose patterns 3
• Consider thrice-daily premixed insulin analogs if twice-daily dosing fails to achieve glycemic targets 1

Pitfalls and Caveats

• Premixed insulins offer less flexibility than basal-bolus regimens for adjusting individual components 1
• Switching between different premixed formulations requires careful monitoring due to different pharmacokinetic profiles
• When transitioning from 70/30 NPH/regular to analog premixes, initial doses are typically similar, but may require adjustment based on glucose monitoring
• Avoid abrupt changes between formulations without appropriate monitoring and dose adjustment

Remember that while analog premixed insulins generally provide better postprandial control and convenience, human insulin premixes remain a cost-effective option for patients with financial constraints 1.