Diabetes Treatment (cont.)

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Medications that affect glycemic control (Symlin, Byetta, Victoza, Bydureon)

Symlin (pramlintide)

Pramlintide (Symlin) is the first in a new class of injectable, anti-hyperglycemic medications for use in patients with type 2 or type 1 diabetes treated with insulin. Pramlintide, the active ingredient in Symlin, is a synthetic analog of human amylin, a naturally occurring neuroendocrine hormone synthesized by pancreatic beta cells that helps control glucose control after meals. Amylin, similar to insulin, is absent or deficient in patients with diabetes. When used with insulin, this compound can improve glycemic control and has additional benefits that cannot be realized with insulin alone.

According to published data, Symlin reduces post meal blood sugar peaks, reduces glucose fluctuations throughout the day, enhances satiety (the sensation of fullness) leading to potential weight loss, and lowers mealtime insulin requirements. Studies have shown it improves A1C beyond the effect of insulin alone.

Symlin is taken just prior to meals, three times a day. It is given in injection form and is used for:

  • Type 2 diabetes, as an additional treatment in patients who use mealtime insulin therapy and have failed to achieve desired glucose control despite optimal insulin therapy, with or without a concurrent sulfonylurea agent and/or metformin.
  • Type 1 diabetes, as an additional treatment in patients who use mealtime insulin therapy and who have failed to achieve desired glucose control despite optimal insulin therapy.

Symlin is considered a therapy option in patients with insulin-using type 2 or type 1 diabetes, that are unable to achieve adequate glycemic control despite individualized insulin management. Insulin-using patients with type 2 diabetes may also be taking a concurrent sulfonylurea agent and/or metformin.

It is important to note that Symlin with insulin has been associated with an increased risk of insulin-induced severe hypoglycemia, particularly in patients with type 1 diabetes. This severe hypoglycemia occurs within 3 hours of taking the Symlin injection.

The major side effect of Symlin is nausea, and this can be reduced with a slow, steady, increase in dose. The other major side effect is hypoglycemia (dangerously low levels of blood sugar). To avoid this, the dose of mealtime insulin should be cut in half when starting Symlin. Of note is the degree of weight loss seen with Symlin therapy. Studies for up to six months show weight loss of greater than six pounds more than placebo (inactive pills).

Byetta (exenatide)

Exenatide (Byetta) is a medication on the market that has its origins in an interesting place--the Gila monster's saliva. Scientists studying this small lizard noted it could go a long time without eating. They found a substance in its saliva that slowed stomach emptying, thus making the lizard feel fuller longer. This substance was similar in nature to a gut hormone found in humans known as GLP-1. GLP-1 is broken down in the body by an enzyme called DPP-IV. So, if you could make a substance like GLP-1 that was not so easy to breakdown, this would have potential benefit; thus, the studies began. Ultimately, after modifying this hormone, exenatide (with the trade name Byetta) was developed.

Byetta is the first in a class of drugs for the treatment of type 2 diabetes called incretin mimetics. Byetta has been shown to have many of the same effects on sugar regulation as GLP-1, so it mimics the body's natural physiology for self-regulating blood sugar. Namely, it slows the release of glucose from the liver, slows stomach emptying thereby regulating delivery of nutrients to the intestine for absorption, and works centrally in the brain to regulate hunger.

Byetta is indicated as additional therapy to improve control of blood sugars in patients with type 2 diabetes who are taking metformin, a sulfonylurea, or a combination of metformin and a sulfonylurea but who have not achieved adequate sugar control. It enhances the way the insulin producing beta cells in the pancreas work. Insulin secretion increases only when blood sugars are high and decreases as blood sugars approach normal. In addition to enhancing the normal physiology of the beta cell, Byetta suppresses glucose release from the liver, slows stomach emptying and the absorption of nutrients including carbohydrate, and reduces intake of food.

Just like Symlin, Byetta is given by injection, but it is given twice a day (usually before breakfast and dinner meals). It comes in a disposable pen form and is available in two doses. The goal is to start with the lower dose for a month or so and then move up to the higher dose if needed and if tolerated. Similar to Symlin, the main side effect is nausea, most likely due to its effects on stomach emptying. This medication is temperature sensitive and it was recommended that the pens be stored at 36 to 46 F (2 to 8 C).

Recently, this has changed, with a recommendation that unopened pens be refrigerated, and once opened the pens can be left at room temperature. The risk of hypoglycemia is still a possibility with Byetta, especially when used in combination with sulfonylureas. Your physician may choose to decrease the dose of some of your other medications when initially evaluating how you respond to Byetta.

Similar to Symlin, weight reduction is seen with Byetta in the majority of patients. This makes it particularly suitable for the typical patient with type 2 diabetes who is also overweight.

A longer acting from of Byetta is currently being considered for approval by the FDA. This would allow for the same benefits (and side effects) without need for such frequent injections.


Bydureon is a longer acting from of exenatide that is administered in a once-weekly injection.

Victoza (liraglutide)

Victoza (liraglutide) is an injectable prescription medicine that improves blood sugar (glucose) in adults with type 2 diabetes when used with a diet and exercise program. Victoza is not insulin. It is not known if Victoza is safe and effective when used with insulin. Victoza is not for people with type 1 diabetes or people with diabetic ketoacidosis. Victoza is not recommended for use in children. Victoza, like Byetta, belongs to a class of medicines known as glucagon-like peptide-1 (GLP-1) receptor agonists, which help the pancreas make more insulin after eating a meal.

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