What is Insulin? Learn More About Types of Insulin!

by Cindy

What is Insulin? Learn More About Types of Insulin!

Diabetes is a chronic health condition that occurs when there is a disruption in normal insulin production from the pancreas.  When insulin production is abnormal blood sugars can rise creating a state of hyperglycemia or diabetes.  Diabetes is a serious health problem and with more and more Americans receiving this diagnosis every year it is important that patients understand this hormone and potential therapy for their diabetes. 

The use of insulin is necessary for all patients with type 1 diabetes who no longer produce any of this important hormone.  Patients with type 2 diabetes often do not initially need to start insulin therapy but as the disease progresses, this often becomes necessary. 

Unfortunately insulin has been stigmatized as a treatment failure and is a feared by many patients with type 2 diabetes.  It is important for type 2 diabetics and their doctors to understand that insulin most closely mimics the natural processes within the body and is most effective for controlling glucose levels quickly and efficiently.  Current research supports the use of insulin in type 2 diabetics because using this medication can reduce the risk of diabetic complications while newly diagnosed patients can learn lifestyle modifications to help improve sugars.  For many patients, one daily injection of long acting insulin can be combined with an oral medication to quickly improve a1c levels.

What is Insulin?

Insulin is a hormone that is produced by special cells within the pancreas that are called beta cells.  Insulin is used by the body to regular blood sugar levels.  Insulin is produced and stored by the pancreas so that it can be released both in response to meals and to maintain normal metabolic functions.  Insulin is released in two key phases, both of which become very important when diabetic patients use insulin to manage their condition. 

Basal Insulin Production

Basal insulin is produced continuously throughout the entire day and works to keep glucose in control outside of meal times.  Commercially produced insulin, called long acting insulin, have been created to mimic this important function. 

Post Prandial Insulin Production

Stored supplies of insulin are released approximately 15 minutes after meals are eaten in response to rising glucose levels in the post prandial period.  Shorter acting insulin is used to bring sugar levels back to a normal range following meals.  

Exogenous Insulin

Exogenous insulin refers to insulin that is developed commercially to be used as a replacement for diabetic patients who no longer produce their own insulin supply.  Exogenous insulin is typically extracted from bovine and porcine pancreases.  Insulin from porcine (pig) sources are most similar to human insulin.  Synthetic products and human-like insulin have been created, are most similar to human insulin and are now the most commonly used products. 

Commerical insulin is measured in units so that the doses can be standardized worldwide.  Vials are most commonly found in standardized concentrations labeled “U-100” which means that there are 100 units in every milliliter (mL).  In extreme cases, different concentrations of insulin solutions can be obtained but the overwhelming majority of patients will use U-100 preparations. 

Types of Insulin

Modern science has provided doctors with a variety of different types of insulin that are used for the management of diabetes today.  These insulin types are divided into categories based on how quickly they act.

Short Acting Insulin

Short acting insulin is also known as “Regular” insulin.  Regular insulin has historically been used to regulate blood sugars after meals because it begins to work within 30 minutes of injection.  They are at their peak effectiveness three hours after meals.  Short acting insulin is typically administered 20 minutes before meals.  Examples of short acting insulin include Novolin R and Humulin R.

Rapid Acting Insulin

Rapid acting insulin has gained popularity in recent years because it works very quickly and are processed by the body faster than regular insulin.  These types of insulin begin to work as early as 10 minutes after injection and are most effective over the first 30 minutes to 3 hours of use.  Rapid acting insulin most closely resembles the natural way that insulin is used by the body after meals.  This type of insulin should be injected no more than 15 minutes before a meal and should be used in conjunction with a basal (long acting) commercial insulin. Examples of rapid acting insulin include Humalog, Novalog and Apidra.

Intermediate Insulin

Intermediate insulin was very popular and commonly used to mimic the background insulin secretion that is needed to keep blood sugar levels stable when diabetic patients are fasting.  NPH is a type of intermediate insulin that is given 2-3 times per day to regulate fasting sugars.  NPH is not appropriate for use to regulate meal time sugars because it takes several hours to begin to work.

Long Acting Insulin

Long acting insulin is also used to simulate the normal function of the pancreas outside of meal times.  These medications can be given once or twice per day, depending on the formulation and are often embraced by type 2 diabetics.  These types of medications should not be used to try to reduce meal time sugars because they begin to work slowly and keep sugars at a steady level throughout the day.  Long acting insulin will not reduce a spike in sugar levels without the help of a rapid or regular insulin.  Examples of long acting insulin include Lantus and Levemir. 

How to Store Insulin

Keeping insulin supplies safe is important to insure that the concentration of the medication remains stable and to prevent infection.  Patients should ask their pharmacist how to store their insulin because not all types of insulin require the same type of storage.  However in general patients on insulin should:

  • Store insulin in the refrigerator or at room temperature (Ask your pharmacist!)
  • Never freeze insulin!
  • Avoid exposure to extreme heat
  • Discard opened vials after 28 days unless otherwise advised by your physician or pharmacist.
  • Avoid exposure to direct sunlight
  • Always check your vial for cloudiness or crystals and discard if it appears abnormal

Insulin is a key component in the treatment of both type 1 and type 2 diabetes.  It works very effectively to gain control of abnormal blood sugar levels.  When carefully used it is very safe and has relatively few side effects.  Patients with type 2 diabetes often fear starting insulin injections due to a stigma of treatment failure and fear of side effects.  Patients and physicians alike need to embrace the use of insulin as an effective tool for management of more than just type 1 diabetes!

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