Insulin is the hormone that helps our body use glucose (sugar). In diabetes, our body is unable to use glucose because of deficiency or ineffectiveness of insulin. In type 1 diabetes, the body cannot make insulin. In type 2 diabetes, the body can make insulin but does not respond to it (called insulin resistance).
Treatment with insulin is needed in all type 1 diabetes patients, and in many patients with type 2 diabetes, especially if they have had type 2 diabetes for a long time.
The normal pancreas makes a small amount of insulin at all times (basal insulin). A significantly greater amount of insulin is produced for one or two hours upon ingestion of food to help the body utilize sugar released from digested food (bolus or prandial insulin).
Depending on the type and severity of diabetes, your physicians will recommend different insulin regimens (Insulin plans). These may or may not be given with oral diabetes medicines.
Commercially available insulin can be broadly divided into two kinds:
- 1. Slow Acting (Long Acting):
This category includes insulin preparations that start acting gradually and their effect lasts for 12-24 hours. Examples include LANTUS®, BASAGLAR®, LEVEMIR®, TOUJEO®, TRESIBA® or NPH (Humulin or Novolin-N).
NPH is intermediate-acting; its effect on blood glucose (BG) lasts for about 12 hours and therefore it may have to be given twice a day. The other insulin preparations in this group have longer durations of action, and they may be given once a day (in the morning or at night).
- 2. Fast Acting (Short Acting):
These insulin preparations are taken before major meals and because of their rapid onset of action, they prevent blood glucose from rising after meals.
Examples include Humolog®, Novolog®, Fiasp®, Lyumjev® or Apidra®. This group starts acting within 10-15 minutes and should generally be taken before one starts eating.
Humulin-R® or Novolin-R® (also called Regular insulin) are older insulin preparations that are taken before a meal. They may take 20-30 minutes to work and may last longer in your system.
Sometimes the slow and fast insulin is mixed in formulations such as Humulin 70/30, Novolin 70/30 (NPH and regular insulin), Humalog 75/25, and Novolog 70/30 (NPH and Humalog/Novolog). These preparations are simple to use and may be useful in older patients who have trouble managing more complex insulin dosing. However, many patients cannot get good BG control as can be achieved by more complicated insulin plans. With mixed insulin formulations meal timing and exercise levels have to be kept similar from one day to another.
Insulin is administered based on a patient’s unique needs. These needs are determined by the following factors:
- Type 1 vs type 2 diabetes
- Other diabetes medicines in patients with type 2 diabetes
- Patient’s ability to ‘handle’ the complexity of the regimen
- Severity of diabetes
- Cost to patients
- Propensity to low BG (hypoglycemia)
Once daily insulin:
In some patients with type 2 diabetes, slow insulin (e.g. Lantus® or Levemir®) is used to supplement oral medications (diabetes pills) and control blood sugars. This method is useful when sugars are only moderately high, and the pancreas can still make some insulin. These patients often take anti-diabetic pills during the day and a slow-acting insulin injection at bedtime. Your physician may recommend starting a small dose (e.g., 10 units at bedtime) and increasing the dose by 2 units every 3 days until the fasting sugar is < 120 mg/dl. Good sugar readings in the morning may allow the diabetes pills to be more effective during the day.
Twice daily insulin:
For some patients with type 2 diabetes, twice daily injections of a combination of ‘slow’ and ‘fast’ insulin may allow fairly good control of blood sugars. Typically a dose of pre-mix insulin (70/30 insulin) is given 10-15 minutes before breakfast and another dose before the evening meal.
Intensive insulin plan (basal-bolus insulin):
The best method to control diabetes with insulin is by administrating the ‘fast’ insulin before each meal (e.g. Humalog®, Novolog®), usually given 5-10 minutes before major meals, and ‘slow’ insulin once daily (Lantus, Tresiba, or Levemir) – given once a day before bedtime. This combination mimics natural insulin release and allows the most flexibility. With the help of diabetes educators, you may learn how to count carbs in your meals and take a proportionaldose of ‘fast’ insulin to cover that meal. An additional sliding scale may be given to cover high blood sugar (please note that Humalog or Novolog is given to cover carbs and high blood sugars.
Insulin Dose Adjustments:
Patients must check blood sugars regularly (3-4 times a day). This will help your doctor adjust insulin doses and detect hypoglycemia (low blood sugar). After receiving in-depth training, some patients may be able to make minor adjustments in their insulin doses to get BG readings within the target range.
- For patients taking Lantus (or other slow-acting insulin preparations) at night, the dose can be increased by ~2 units every 3-5 days if the fasting BG (early morning/ before breakfast) is >130-140 mg/dL.
- If BG is already high at bedtime, then the evening (dinner) dose of diabetes pills or evening (pre-dinner) fast-acting insulin may need to be increased.
- For patients taking premixed insulin (70/30):
If BG is high at lunch and dinner time (>140-175 mg/dL), the morning dose may be increased by 2 units (after 3-5 days of observation).
If BG is high at bedtime (>140 mg/dL) or in the fasting state (>140mg/dL), the dinner dose of 80/30 insulin may be increased by 2 units (after 3-5 days of observation).
- If BG is low (<70 mg/dL), a reduction of insulin dose may be necessary.
You should work with your healthcare provider (or certified diabetes educator) to plan your insulin regimen. They can help you develop and ‘fine-tune’ the insulin doses needed to improve your BG and achieve it in a safe manner.
Diabetes is a chronic disease. By taking charge, you can control it and prevent all of the complications of diabetes. American Diabetes Association (www.diabetes.org) has many publications and other tools that may help you control your diabetes. Good luck!
This information is for general knowledge & is not a substitute for medical advice your doctor recommends.
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