Is 20 units of Toujeo (insulin glargine) a suitable starting dose when switching from 70/30 insulin (Novolog Mix 70/30 or Humalog Mix 75/25) at 15-25 units twice daily (BID), with titration by 3 units every 3-4 days for glucose levels remaining above hyperglycemia (>200 mg/dL)?

Switching from 70/30 Insulin to Toujeo: Dosing Strategy

Starting at 20 units of Toujeo when switching from 70/30 insulin at 15-25 units BID is too low and will likely result in inadequate glycemic control; you should calculate approximately 80% of the total daily dose of the 70/30 insulin (24-40 units total daily dose × 0.8 = 19-32 units), making 25-30 units of Toujeo a more appropriate starting dose, with titration by 2-3 units every 3 days based on fasting glucose targets rather than waiting for glucose >200 mg/dL. 1

Rationale for Dose Conversion

When transitioning from premixed insulin to basal insulin, the conversion requires careful consideration of the total daily insulin dose:

• Your patient is receiving 30-50 units total daily dose (15-25 units BID) of 70/30 insulin, which contains both basal (70% NPH) and prandial (30% rapid-acting) components 1

• The basal component alone from 70/30 insulin represents approximately 21-35 units of intermediate-acting insulin daily (70% of total dose)

• Standard conversion to basal analog typically uses 80% of the current basal insulin dose or can be done unit-to-unit with subsequent titration 1, 2

• Starting at only 20 units would represent a significant reduction from the basal component they're currently receiving, risking hyperglycemia

Recommended Starting Approach

Initial Toujeo dose should be:

• Calculate total daily dose of 70/30 insulin (30-50 units in your case)
• Start Toujeo at 80% of this total daily dose: 24-40 units once daily 1
• A practical middle-ground starting dose would be 25-30 units once daily 1

Titration strategy should be more proactive:

• Increase by 2 units every 3 days to reach fasting plasma glucose goal (typically 80-130 mg/dL), not waiting for glucose >200 mg/dL 1
• The ADA recommends titrating to achieve fasting blood glucose targets, not just responding to severe hyperglycemia 1
• Your proposed 3-unit increases every 3-4 days are acceptable but should target fasting glucose goals of 80-130 mg/dL rather than only responding to glucose >200 mg/dL 1

Critical Considerations When Switching

Loss of prandial coverage:

• 70/30 insulin provides both basal and mealtime insulin coverage 1
• Switching to Toujeo (basal-only) eliminates the 30% rapid-acting component (approximately 9-15 units daily of prandial insulin) 1
• You must monitor postprandial glucose closely and consider adding mealtime insulin or a GLP-1 receptor agonist if A1C remains above target despite adequate fasting glucose control 1

Hypoglycemia risk:

• The risk of nocturnal hypoglycemia should actually decrease with basal insulin compared to 70/30 insulin 3, 4
• However, if the patient experiences hypoglycemia during titration, reduce the dose by 10-20% 1

Monitoring requirements:

• Focus on fasting plasma glucose for basal insulin titration 1
• If fasting glucose is controlled but A1C remains elevated, this signals inadequate postprandial coverage requiring intensification 1

Alternative Consideration

If postprandial control becomes problematic:

• Consider adding a single injection of rapid-acting insulin before the largest meal (starting at 4 units or 10% of basal dose) 1
• Or consider adding a GLP-1 receptor agonist for postprandial glucose control with additional benefits of weight loss and lower hypoglycemia risk 1

Common pitfall to avoid: Starting basal insulin too conservatively when switching from premixed insulin leads to prolonged hyperglycemia and delayed achievement of glycemic targets, which increases morbidity risk 1. The evidence consistently shows that timely dose titration after insulin initiation is critical for outcomes 1.