What are the 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.
Characteristics to consider with your insulin include
- 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.
What are 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.
What are Oral Glucose Lowering Medications?
A person with type 2 diabetes will often require one or more medications to keep blood glucose levels under control. These medications are in tablet form and are taken by mouth on a daily basis. There are eight different classes of these medications, and they each work a little bit differently.
- Sulfonylureas: Increase the amount of insulin made by the pancreas
- Meglitinide: Increase the amount of insulin the pancreas releases
- Biguanide: Decrease the amount of glucose made by the liver
- Thiazolidinedione: Increases the sensitivity of the body to insulin
- Alpha-glucosidase inhibitor: Slows down the rate of glucose absorption by the small intestine
- Dipeptidyl-peptidase 4 inhibitors: Makes the naturally occurring incretins work longer and better. See the section on Incretins and Amylin
- Sodium-glucose transporter 2 (SGLT2): Causes excess glucose to be excreted in the kidneys
- Bile acid sequestrant: Can lower both cholesterol snd glucose in the blood
Your doctor may also prescribe a combination medication, which contains two of these medications in one pill.
How do my Medications Affect my Diet?
Medications for diabetes are designed to lower blood glucose. It is important that you follow your meal plan as designed by your dietitian or doctor. Your diet needs to be matched to your medications, and your medications need to be matched to your diet. Taking oral medications for diabetes doesn’t just “cover” whatever you feel like eating. Eating consistently so that there is a good match may be hard. Eating a lot one day and not much the next day usually means that on neither day was your medication and food matched.
Hypoglycemia can occur if meals are skipped while taking one of these medications. Check with your health care professional if this is a concern for you.
This site was last updated June, 2014.
This is a source of information only, and is not medical advice.