Insulin Conversion from Lantus to NPH

Introduction to Conversion

When converting from Lantus (insulin glargine) 20 units twice daily to NPH twice daily, the American Diabetes Association recommends using 80% of the total Lantus dose as the starting NPH dose, which equals 32 units total NPH per day, split as approximately 21 units before breakfast and 11 units before dinner 1, 2, 3

The current total daily Lantus dose is 40 units, and the starting NPH dose should be 32 units total (80% of 40 units), according to the American Diabetes Association guidelines 1, 2, 4
This dose reduction accounts for the different pharmacokinetic profiles and helps prevent hypoglycemia during the transition, as recommended by the American Diabetes Association 2, 4
The morning dose (before breakfast) should be 21 units (2/3 of total), and the evening dose (before dinner) should be 11 units (1/3 of total), based on the American Diabetes Association guidelines 1, 2, 3

The American Diabetes Association recommends monitoring fasting plasma glucose to assess adequacy of the evening NPH dose, and increasing the dose by 2 units every 3 days if glucose remains above target without hypoglycemia 2, 3
For hypoglycemia, the American Diabetes Association suggests determining the cause, and if no clear reason exists, lowering the corresponding dose by 10-20% 1, 2, 4

The American Diabetes Association acknowledges NPH as an appropriate basal insulin option when cost is a barrier, due to its significant cost savings compared to Lantus 1, 2, 3
Patients should be counseled about the increased risk of hypoglycemia with NPH, particularly nocturnal episodes, and prescribed glucagon for emergencies, as recommended by the American Diabetes Association 2, 3

The American Diabetes Association recommends not converting unit-for-unit, but instead using the 80% reduction to prevent hypoglycemia during transition, and not giving NPH at bedtime initially, but instead using the 2/3 morning, 1/3 evening split 1, 2, 3, 4
The American Diabetes Association also recommends not delaying dose adjustments, but instead reassessing every 3 days and titrating based on glucose patterns 2, 3