How to convert a patient from 22 units of Novolin (Novolin 70/30, a mix of NPH and regular insulin) twice daily to a long-acting insulin like glargine (Lantus or Basaglar)?

Converting from Novolin 70/30 to Long-Acting Insulin

When converting from 22 units of Novolin 70/30 twice daily (total 44 units/day) to a long-acting basal insulin like glargine, start with 80% of the total daily dose (approximately 35 units) given once daily, and closely monitor for hypoglycemia during the transition. 1

Understanding the Current Regimen

Your patient is currently on:

• Total daily insulin: 44 units (22 units AM + 22 units PM)
• Composition of Novolin 70/30: 70% NPH (intermediate-acting) + 30% regular insulin (short-acting)
• Basal component: Approximately 31 units/day (70% of 44 units)
• Prandial component: Approximately 13 units/day (30% of 44 units) 2

Conversion Protocol to Glargine

Initial Dosing Strategy

Calculate 80% of the total NPH component when switching from twice-daily NPH-containing insulin to once-daily glargine 1:

• Total NPH component: ~31 units/day
• Starting glargine dose: 25 units once daily (80% of 31 units)

Alternatively, using the total daily dose approach:

• Starting glargine dose: 35 units once daily (80% of 44 units total) 1

The more conservative approach is to use 80% of the total daily dose (35 units), as this accounts for the loss of prandial coverage and reduces hypoglycemia risk. 1

Timing of Administration

• Administer glargine once daily at the same time each day (can be morning, evening, or any consistent time) 1
• The FDA label specifies that glargine provides up to 24 hours of basal coverage without a pronounced peak 1, 3

Critical Considerations for Prandial Coverage

Important caveat: Novolin 70/30 provides both basal AND prandial insulin coverage. When converting to glargine alone, you are only replacing the basal component 2, 1.

Options for Managing Prandial Needs:

1. If the patient has type 2 diabetes and adequate glycemic control:

   • Start with glargine 35 units once daily alone
   • Monitor closely for 3-5 days
   • Add prandial insulin only if postprandial hyperglycemia develops 2

2. If the patient has type 1 diabetes or significant postprandial hyperglycemia:

   • Must add short-acting insulin at mealtimes (4 units per meal or 10% of basal dose per meal as starting point) 2, 1
   • Consider starting with the largest meal first if simplifying 2

3. If the patient prefers to avoid multiple injections:

   • Consider maintaining a twice-daily NPH regimen instead: 80% of current total dose (35 units), split as 2/3 morning (23 units) and 1/3 evening (12 units) 2, 4

Monitoring and Titration Protocol

Initial Monitoring (First 3-5 Days)

• Check blood glucose at least 4 times daily: fasting, pre-lunch, pre-dinner, and bedtime 5
• Watch specifically for nocturnal and fasting hypoglycemia (the long-acting effect of glargine may delay recovery from hypoglycemia) 1, 6

Dose Adjustment Algorithm

For hypoglycemia:

• Determine the cause; if no clear reason, reduce glargine by 10-20% 2, 7
• The long-acting profile means hypoglycemia may occur hours after injection 1

For persistent hyperglycemia (fasting glucose above target):

• Increase by 2 units every 3 days until fasting glucose reaches target 7
• Alternatively, increase by 10-15% twice weekly 2

For postprandial hyperglycemia:

• This indicates need for prandial insulin coverage, not increased basal insulin 2
• Add rapid-acting insulin with meals (start with 4 units at the largest meal) 2

Common Pitfalls to Avoid

1. Forgetting about prandial coverage: Glargine only provides basal insulin. Patients previously on 70/30 were getting prandial coverage that will be lost 2, 1

2. Not reducing the dose enough: The FDA label specifically recommends 80% of total NPH dose to reduce hypoglycemia risk 1

3. Mixing glargine with other insulins: Glargine should never be mixed with other insulins in the same syringe due to its low pH 2, 1

4. Inadequate monitoring during transition: Increase glucose monitoring frequency during any insulin regimen change 1

5. Expecting immediate 24-hour coverage: Some patients may require twice-daily glargine if once-daily dosing doesn't provide full 24-hour coverage 8

Alternative: Simplified Twice-Daily NPH Regimen

If the patient prefers fewer medication changes and simpler dosing:

• Total dose: 35 units/day (80% of current 44 units)
• Morning: 23 units (2/3 of total)
• Evening: 12 units (1/3 of total)
• This maintains both basal and some prandial coverage 2, 4