Back to Diabetes Basics Symlin


Symlin (pramlintide acetate) is a new class of drug for treating both type 1 and type 2 diabetes. Symlin is a synthetic version of the naturally occurring hormone amylin, which is secreted along with insulin by beta cells in response to eating. Amylin helps the body to regulate how quickly nutrients from food are converted into glucose and delivered into the blood, while insulin regulates how quickly the glucose is absorbed by cells. Thus insulin and amylin work together in the process of metabolism.

In people with type 1 diabetes, who have lost beta cells due to autoimmunity, the body doesn't produce amylin, just like it doesn't produce insulin. In people with type 2 diabetes, beta cells don't increase the secretion of amylin in response to food like they should.

This diagram illustrates how Symlin and insulin work in the body.
Symlin comes only in vials at this time.

How Symlin Works

So what exactly does Symlin do? From the Symlin web site we learn that:

  1. Symlin slows gastric emptying.
  2. Symlin suppresses postprandial glucagon secretion leading to suppression of endogenous glucose output from the liver.
  3. Symlin modulates appetite by enhancing satiety. This effect is independent of nausea and may lead to weight loss.

The slowing of gastric emptying means that you must decrease pre-meal insulin to prevent hypoglycemia.

Impact of Symlin

Adults with type 1 who use Symlin report several effects of Symlin. First, they feel less hungry so they eat less. Second, they report a significant decrease in post-prandial blood sugar levels compared to before they started using Symlin, even though they all use less insulin to cover a given amount of carbs. This is due to Symlin delaying the absorption of food. Pump users report having to use extended boluses for any meal at which they take Symlin because of this delay.

The following graphs illustrate clearly the effect of Symlin on post-prandial blood glucose levels in an adult with type 1 diabetes. Note that the use of Regular insulin results in a smoother glucose profile compared with Lispro, due to the delayed absorption of food. The longer time of action for Regular insulin is similar to the delayed action of an extended bolus. In both cases, pre-meal insulin levels were reduce significantly.

Symlin with Lispro for mealtime insulin
Symlin with Regular for mealtime insulin

Charts from

Symlin has also been shown to reduce the fluctuations in glucose levels quite significantly in patients with type 1 and type 2 diabetes. With scientists now considering glucose fluctuations as important as HbA1c in the overall risk of developing complications, reducing fluctuations is important. This graph shows the effect of Symlin on daily fluctuations of glucose after 6 months in patients with type 2 (n=166) and type 1 (n=265):

Chart from

Finally, Symlin has been shown to result in sustainable weight loss.

Using Symlin

Like insulin, Symlin has to be injected. Symlin cannot be mixed with insulin, though one study found essentially no effect when mixed. Symlin is also not approved for use in an insulin pump, but people have successfully used Symlin in a pump dedicated just to Symlin. These people wear two pumps -- one for insulin and one for Symlin. Using Symlin in an insulin pump is off-label and should be discussed with your diabetes team.

Symlin is used only when a meal will contain a significant amount of calories and carbohydrates, typically at least 250 calories and at least 30 grams of carbs. Mealtime insulin is always reduced when taking Symlin -- and often reduced significantly. The literature from Amylin recommends reducing mealtime insulin by 50% when starting Symlin. This is essential to reduce the risk of severe hypoglycemia. Symlin can make a big difference in post-prandial blood sugars, but it must be used with care, and that includes reducing mealtime insulin and checking blood sugar levels often following meals.

In addition to the increased risk of hypoglycemia if you don't reduce mealtime insulin, Symlin can cause nausea, particularly at the higher doses. Most people find that the nausea subsides. Many people report never having nausea at all.

If you're looking to improve your diabetes control, especially to reduce post-prandial glucose excursions, talk with your diabetes team about Symlin.

If you're new to Symlin, the SYMLIN Support Program may help.

As of July 2007, Symlin is FDA-approved only for adults with type 1 or type 2 diabetes. Teens with type 1 can and do use Symlin, but such use if off-label.

For More Information

Selected Studies About Symlin

Logo   Amylin Pharmaceuticals, Inc.
9360 Towne Centre Drive
San Diego, CA 92121
858-552-2200 phone
858-552-2212 fax

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Last Updated: Thursday February 27, 2014 19:28:21
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