What parameters should I set for 70/30 (Novolin, Humulin) insulin therapy?

Should You Set Parameters on 70/30 Insulin?

Yes, you should absolutely set specific parameters for 70/30 insulin, including glucose targets, hold parameters for hypoglycemia, and monitoring frequency—but critically, 70/30 insulin should be avoided entirely in hospitalized patients due to unacceptably high hypoglycemia risk. 1

Critical Context: Inpatient vs. Outpatient Use

Hospitalized Patients: Avoid 70/30 Insulin

• 70/30 premixed insulin is contraindicated in the hospital setting due to significantly elevated rates of iatrogenic hypoglycemia compared to basal-bolus regimens 1
• The American Association of Clinical Endocrinologists explicitly recommends against using premixed insulin formulations in hospitalized patients 1
• For hospitalized patients requiring insulin, use scheduled subcutaneous basal-bolus regimens (basal + nutritional + correction components) or IV insulin infusion in critical care 2

Outpatient/Ambulatory Patients: Parameters Are Essential

If 70/30 insulin is being used in the outpatient setting (where it is appropriate), the following parameters must be established:

Glucose Target Parameters

Initiation Thresholds

• Start insulin therapy when blood glucose persistently exceeds 180 mg/dL (10.0 mmol/L) 2
• Once insulin is initiated, target glucose range should be 140-180 mg/dL (7.8-10.0 mmol/L) for most patients 2

Individualized Targets

• More stringent goals of 110-140 mg/dL (6.1-7.8 mmol/L) may be appropriate for select stable patients if achievable without significant hypoglycemia 2
• Higher targets may be necessary for patients with severe comorbidities, terminal illness, or limited monitoring capability 2

Hold Parameters for Hypoglycemia

Critical Hypoglycemia Thresholds

• Modify the insulin regimen when blood glucose falls below 70 mg/dL (3.9 mmol/L) unless easily explained by a missed meal 2
• Consider reassessing the regimen if glucose levels fall below 100 mg/dL (5.6 mmol/L) to proactively prevent hypoglycemia 2
• Severe hypoglycemia is defined as <40 mg/dL (2.2 mmol/L) in hospitalized patients, though cognitive impairment begins at <50 mg/dL (2.8 mmol/L) 2

Action Steps for Hypoglycemia

• Early recognition and treatment of mild-to-moderate hypoglycemia (40-69 mg/dL) prevents deterioration to severe episodes with adverse outcomes 2
• Hold the next dose of 70/30 insulin if glucose is <70 mg/dL and contact the prescribing provider for dose adjustment 2

Monitoring Frequency Parameters

Outpatient Monitoring

• Patients on 70/30 insulin require frequent blood glucose monitoring during initiation and dose adjustments, targeting both fasting and postprandial levels 1
• The American Diabetes Association recommends 4-6 capillary glucose determinations per day for patients on insulin therapy 3
• Increase monitoring frequency during the first 1-2 weeks after conversion from other regimens 4

Specific Timing for 70/30 Insulin

• Monitor fasting glucose (to assess overnight NPH component) 4
• Monitor 2-hour postprandial glucose (to assess regular insulin component) 4
• Monitor pre-dinner glucose (to assess morning NPH carryover) 4

Dosing Distribution Parameters

Critical Dosing Rules

• Never use equal morning and evening doses—this significantly increases nocturnal hypoglycemia risk 4
• Distribute as approximately 2/3 of total daily dose before breakfast and 1/3 before dinner 1
• For insulin-naive patients, start with 0.3-0.5 units/kg/day total daily dose, using lower doses for elderly, renally impaired, or those with poor oral intake 1

Timing Parameters

• Administer 30 minutes before meals (for human insulin 70/30 formulations like Novolin 70/30 or Humulin 70/30) 1
• Morning dose given before breakfast, evening dose before dinner 1

Adjustment Parameters

Dose Adjustment Algorithm

• Adjust doses by 10-20% based on glucose patterns 4
• Increase evening dose if fasting glucose is elevated (targets morning glucose) 4
• Increase morning dose if pre-dinner glucose is elevated (targets afternoon glucose) 4
• For patients already on higher insulin doses (≥0.6 units/kg/day), consider a 20% reduction in total daily dose when switching to prevent hypoglycemia 1

Essential Clinical Considerations

Patient Selection Criteria

70/30 insulin is only appropriate for outpatients who have:

• Consistent meal timing and carbohydrate intake (irregular meals contraindicate premixed insulin) 5, 1
• Ability to perform frequent self-monitoring 5
• Understanding of hypoglycemia recognition and treatment 5

Common Pitfalls to Avoid

• Never mix insulins in the same syringe—this creates unpredictable pharmacokinetics 4
• Do not convert from basal insulin on a 1:1 basis without adjusting the morning/evening distribution 5
• Emphasize critical importance of consistent meal timing to patients to prevent hypoglycemia 5
• Continue metformin but discontinue sulfonylureas, DPP-4 inhibitors, and GLP-1 agonists when using multiple-dose premixed insulin 5

When to Avoid 70/30 Entirely

• Any hospitalized patient 1
• Patients with irregular meal timing or variable carbohydrate intake 5, 1
• Patients requiring maximum flexibility in meal planning 5
• Type 1 diabetes patients (not appropriate as monotherapy) 1

Documentation Requirements

When ordering 70/30 insulin, your parameters should explicitly include:

• Target glucose range (typically 140-180 mg/dL for most patients) 2
• Hold parameters (hold if glucose <70 mg/dL) 2
• Monitoring frequency (minimum 4 times daily during adjustment) 3
• Specific dosing times (30 minutes before breakfast and dinner) 1
• Dose distribution (2/3 morning, 1/3 evening) 1
• Hypoglycemia protocol (treatment plan for glucose <70 mg/dL) 2