Diabetes is a disease in which the glucose in the blood is higher than normal. High blood glucose is called hyperglycemia.
Glucose is a type of sugar coming from foods containing carbohydrates and is found in everyone’s blood. Glucose is transported through the blood to all tissues and organs to be used for energy.
Blood glucose should not be too low (hypoglycemia) or too high (hyperglycemia). The body usually keeps blood glucose within a certain range. When blood glucose begins to rise above normal, it either enters cells to be used for energy, or it is stored. If it is stored for future use, it will be converted to glycogen or fat. Glycogen is a “quick fuel”that is found in muscle and the liver.
When blood glucose needs to enter a cell to provide it with energy, it often needs the help The body is normally able to control blood glucose levels using of a hormone called insulin. Insulin is released by the pancreas in response to increased levels of glucose in the blood. Insulin, blood glucose and the cell’s receptor all work together to move the glucose into the cell.
With diabetes, however, the body has trouble making or using insulin. For this reason, blood glucose levels rise and hyperglycemia occurs
Types of Diabetes
Type 1 diabetes can occur at any age. Type 1 diabetes is called an autoimmune disease, because the immune system attacks the person’s own cells. In this type of diabetes, cells in the pancreas that produce insulin are the target of the body's immune system and are eventually destroyed. For this reason, people with type 1 diabetes produce no insulin so glucose cannot get into the cells
Type 2 diabetes is the most common form of diabetes. With type 2 diabetes, the receptors on the cells become resistant to insulin and therefore cannot let glucose into the cell. Type 2 diabetes may also result if the body does not make enough insulin. Both problems with the cell receptor or with the amount of insulin produced, lead to high blood glucose levels. Being overweight and inactive increases the chance of developing type 2 diabetes.
Insulin Characteristics to consider
Onset - how quickly it will start working
Peak - the time when the insulin is most effective in lowering blood glucose. Note that basal insulin has no peak so is always the same in terms of effectiveness.
Duration - how long it continues to have an effect on your blood glucose
Strength - the most common strength is U-100, which means it has 100 units of insulin per 1 milliliter of fluid. Insulin at U-500 and U-40 are available in some countries.
Types of Insulin
Insulin is classified based on how quickly it takes effect. There are four categories:
Rapid acting should be taken just before or just after eating. It begins to lower blood glucose in less than 15 minutes. It continues to work for about 2 to 4 hours. Common rapid acting insulins include Insulin glulisine (Apidra), insulin lispro (Humalog), and insulin aspart (NovoLog).
Short acting should be taken 30 minutes before a meal. It begins to lower blood glucose within 30 minutes to 1 hour. It lasts for about 3 to 6 hours. Common types are Humulin R and Novolin R.
Intermediate acting has an effect for 14-20 hours, depending on the type,** so it is typically only taken once per day. Common types are NPH such as Humulin N or Novolin N.
Long acting has an effect for 20-30 hours, depending on the type, so it is only taken once per day. This basal insulin has no peak. It is taken once per day. Common types include insulin detemir (Levemir) and insulin glargine (Lantus)
Insulin can be packaged in vials, pens/cartridges, or inhaled. There are also pre-mixed insulins that contain a combination of insulin types described above.
Incretins and Amylins
Incretins and Amylins are both naturally produced hormones that have different actions to control blood glucose. Inretins are secreted from the gut to stimulate insulin secretion in response to eating food. The medication works in the same way. Amylins are secreted by the pancreas. They slow emptying of the stomach contents into the gastrointestinal tract, lower hunger sensations, and effect of hormones involved in blood glucose regulation.
Incretin medications: Exenatide (Byetta™) and Liraglutide (Victoza®) are injected medications that mimics the action of incretin. A doctor may prescribe one of these for patients with type 2 diabetes who have not achieved glucose target goals using metformin, a sulfonylurea, or both (see next section for information on these medications).
Dipeptidyl-peptidase 4 inhibitors: These medications make the naturally occurring incretins work longer and better. These include sitagliptin (Januvia), saxagliptin (Onglyza®), and linagliptin (Tradjenta). Thes medications are taken by mouth. This medication may help lower fasting blood glucose and blood glucose after meals. A doctor may prescribe these alone or in combination with metformin or thiozolidinedione (see next section for information on these medications).
Amylin Analog: Pramlintide (Smylin™) is a synthetic hormone of amylin that is given by injection. A doctor may prescribe pramlitintide if a person who takes insulin to control blood sugars after meals is not reaching desired blood glucose goals. It can be used in both type 1 and type 2 diabetes.