Gettysburg Medical News
The Clinical View
by P.E. Hoffsten, M.D.
28  Aug  2002

THE STORY OF INSULIN

      For practical purposes, virtually all of our energy used in daily life comes from glucose.  It was known more than 2000 years ago that individuals sometimes get sick and begin passing lots of  “sweet urine”.  Just how the ancients figured out that urine was sweet is not recorded and I am not sure I want to know.  They knew there was such a thing, the people that were like that got sick and the children like that died young.  Thus came the name diabetes meaning lots of urine and mellitus meaning sweet.

     It wasn’t until the 1860’s that early scientists discovered the material that prevented diabetes came from the pancreas.  Then began a search to find out what product made by the pancreas kept the person from being diabetic.  By 1920, Banting and Best working in Canada isolated insulin and purified it enough to treat a child that had juvenile onset diabetes.  They were awarded the Noble Prize in medicine for this discovery in 1923.  Soon insulin was being made from beef and pork pancreas and sold commercially.  These preparations were virtually life saving for the “juvenile onset diabetic” whose pancreas had been infected by a virus that killed that child’s ability to make insulin.  These children are insulin deficient and respond very well to the beef and pork preparations. Unfortunately, the beef and pork preparations were not very pure and repeatedly injectingthis material on a daily basis made some people allergic to the preparations. The preparations
often were ineffective because of the diabetics making antibodies to the beef and pork impurities.

     In the 1970’s, a whole new technology developed called “Recombinant Technology”.  According to this new discovery, the gene for making insulin was isolated and incorporated into the genetic code for a bacteria.  Somehow, the bacteria got the message that they were to supposed to make human insulin.  Now, human insulin could be made remarkably pure just from a barrel of bacteria.  For practical purposes, virtually all of the insulin on the market today is made by this technology.  The use of animal insulins has been phased out.

     The next question is “Who should be using insulin?”  Insulin should be used by most patients whose blood sugars cannot be controlled by diet, exercise, and oral medications.  There is a blood test called Hemoglobin A-1-C that measures the person’s average blood sugar has been for the previous 3 months.  If this test exceeds 7% with person’s best diet, exercise and oral medication effort, insulin should be considered.

     Obviously, there are a number of special considerations for a person to start insulin.  The idea of self-injecting a medicine each morning or perhaps multiple times per day is pretty foreign to most people.  The person has to be responsible enough to follow dietary instructions to eat on a regular basis and monitor blood sugars appropriately.  The person has to be capable of properly drawing up their insulin dosage and administering with the right technique in the right part of the body.  Not everyone can do this but there are now techniques available so that even a blind person can self-administer their own insulin on a reliable daily basis.

     The next question relates to what kind of insulin to use and the schedule for administration.  The human body normally makes one kind of insulin and secretes it according to need based upon the body’s measurement of the blood sugar.  Commercial preparations are now very complicated.  There is so called rapid-acting insulin which include regular insulin (Humulin R).   This costs around $25.00 for a 10 ml bottle of U100.  The U100 means that there are 100 units of insulin per ml of solution.  If a person were taking 20 units of regular insulin in the morning, they would use 0.2 ml of solution costing about $ .50.  There are two other insulins that are very rapid acting.  One of these is called Lispro (Humalog).  This costs roughly twice as much as Humulin N.  The third rapid acting insulin is called insulin Aspart (Novalog) which also costs about twice as much as Humulin R.  The advantages of these latter two more expensive preparations is the rapidity with which they act.  With Humalog and Novalog, the person must be sitting down at the table with food in front of them before it is injected or the potential for low blood sugars and insulin reactions can be a problem.

     The second family of insulins is called intermediate acting insulin.  Included in this group is NPH insulin (Humulin N) with the same cost as Humulin R.  Thus if a person took 20 units of Humulin N in the morning, they would use 0.2 ml of solution costing about $ .50. Novalin N is another intermediate acting insulin at the same price.  For individuals who have difficulty with drawing solutions up, or are visually impaired, there are special pens in which the person can simply dial in the amount of insulin needed, touch the device to the skin, press a button and the insulin is automatically injected in the right amount.  These are much more expensive.  The cost is between $70.00 and $100.00 per bottle of insulin or about four times as much as simple Humulin N.  Humulin N is probably the most commonly used insulin and has a peak effect between four and ten hours after the insulin is administered.  If a person takes a shot of Humulin N in the morning, the peak effect will occur sometime around lunch or soon thereafter.  The person has to be careful that they do eat an adequate amount of lunch in order to avoid very low blood sugars that can occur if insulin is administered and then the person doesn’t eat.  The last group of insulins are the so called long-acting.  Ideally it would be useful for a person to have a small amount of insulin administered continuously to combat blood sugars that tend to rise even when the person isn’t eating.  In the past, there was a product called PZI insulin that is now off the market.  It has been replaced with Humulin L and Novalin L.  Unfortunately, neither of these preparations provided the desired continuous slow administration of insulin from a single injection all day.

     Recently on the market is a product called glargine insulin (Lantus).  This product costs around $42.00 per bottle as compared to $25.00 per bottle for the Humulin or Novalog insulins.  The advantage of Lantus insulin is the continuous slow absorption of the product even though it is injected only once a day.  In my recent experience with this new product, highly variable blood sugars really have been brought under better control with a single daily injection.

    The right schedule for using insulin, considering the economics and convenience while achieving adequate control of blood sugars, is a very individual consideration.  The healthcare professionals at your local clinic are aware of the complexities of this problem and can help in designing an insulin protocol that works for the individual person.  In the past, insulin treatment was often started in a hospital setting but that is no longer a necessity.  Your local clinics provide the service of helping initiate the right dose of insulin and teaching the individual how to monitor blood sugars to best control diabetes and avoid complications.