Insulin Therapy Regimens

To optimize glycemic control, an individual would need to receive small amounts of insulin continuously (basal), with boluses of insulin before meals and snacks. Adjust the dose based on self-monitoring of glucose levels, HbA1C, weight, lifestyle and other concurrent conditions.

Insulin Therapy for Type 1 diabetes

Successful insulin therapy for type 1 diabetes requires the co-ordination of the following factors:

Properly titrated insulin dose

Diet
Physical activity
Blood glucose monitoring
Patient education
Readily accessible medical support

There are 2 main insulin regimens

Twice-daily injections of mixed intermediate (cloudy isophane) or long-acting insulin with a short acting (clear soluble) insulin.

The basal bolus regimen: This is particularly suitable for patients with irregular meal times or hectic lifestyles. This consists of intermediate acting insulin at bedtime (to provide the basal insulin requirement) with short acting insulin before each meal.

Multiple Dose Insulin (MDI) regimen: Here a combination of short and long acting insulin (Mixtard 30:70 0r 50:50) is given prior to breakfast and dinner, while a short acting insulin is given at lunch. This regime can be modified in numerous ways to suit the patient's needs, e.g. long acting insulin may be added at bedtime.

Nowadays an entirely new dimension has been added with the availability of ultra short acting Lispro/Aspart insulin and the very long acting Glargine (Lantus) insulins. Glargine insulin is given at bedtime, with the ultra short insulins being administered prior to each major meal.

Self-monitoring of blood glucose (SMBG) with or with a glucometer is recommended at least once daily. Testing time should be changed frequently with the majority of the readings being pre-meal or at bedtime.

Insulin therapy for Type 2 diabetes

Insulin therapy for type 2 diabetes can be supplementary or absolute depending upon the indication. Intermediate acting isophane insulin works well on its own in these patients but a soluble component is often needed to achieve good glycemic control. Soluble insulin can be added if postprandial hyperglycemia 2 hours after a meal is excessive (> 180 mg/dl). A few elderly patients can be managed on once daily lente insulin. Lente insulin is regular insulin complexed with zinc to form a long acting suspension and cannot be mixed with soluble insulin.

Mixing of Insulin

When mixing of two different types of insulin is required in a single syringe then mutual contamination of the two vials must be avoided. What is equally important is that you must always load the rapid acting insulin first and then the intermediate or long acting insulin. If you do the reverse then you are likely to change the time action profile of the short or rapid acting insulin. Once the injection is prepared inject immediately and definitely not after 5 minutes.