I have a patient with type 2 diabetes who is in the hospital right on a sliding scale insulin regimen and is being considered for Lantus. I was approached by a resident and asked how to convert her sliding scale insulin dose (Regular insulin) to a daily dose for Lantus, but I have been unsuccessful in finding the answer in primary literature. Can you provide any methods?

There is no magic formula. Usually, we take all of the total daily dose of intermediate based insulin for 24 hours and start with 80% of that dose as a single bedtime Lantus (insulin glargine) dosage. if people are already on multidose insulin intensified programs, this is too much of a cutback. If they have not been doing well beforehand, then this is a safe starting place. We do some pre and one to two hour postprandial blood glucose readings for a few days before making such a switch and begin to create algorithms with either Humalog or NovoLog as the bolus program. Using approximately 1 unit of short-acting analog to cover about 15 grams of carbs is also a good starting place.

After the first day, everything is empirical based upon continued pre and postprandial monitoring. We push the Lantus dose (or cut it) based upon overnight blood glucose readings and especially fasting blood glucose readings. We adjust the meal-time algorithms based upon pre and postprandial readings as well. Monitoring is the key while keeping amounts of food, carbs and activity as steady as possible for several days. Sometimes the Lantus does not last 24 hours and we add either a morning dose of Lantus to the bedtime dose — or a small amount of lunchtime NPH. This would cover the late afternoon hyperglycemia as the bedtime Lantus effect wanes.

Sometimes snacks that were warranted on previous insulin programs are no longer need so that cutting back or eliminating afternoon food/snack will also prevent pre-dinner hyperglycemia. Same rule, however: use blood glucose readings as your guide and don’t go by previous assumptions. In very young children, sometimes we use Lantus before breakfast and not at bedtime, but this has not been so commonly seen in adults, although it is certainly possible — all based upon blood glucose readings.

SB