This will be the first of several blog posts that I have been working on for the past month, all written with the Symlin novice in mind and with the intent of encouraging as many of you as possible to start on Symlin therapy. I do not work for Amylin (makers of Symlin), or even in the pharmaceutical or health care fields. I do not own Amylin stock. I decided to write this guide because Symlin is so extraordinarily effective at mitigating some specific issues many Type 1s consistently encounter and struggle with, including post-prandial hyperglycemia, weight management, insulin dosing, and appetite control. Given its rather remarkable benefits it is also extraordinarily underused by the Type 1 population as a whole, and in my opinion this is because Amylin has not been successful in effectively communicating these benefits to Type 1s.
Please feel free to comment on my posts with criticisms or correct me if I make a mistake.
What is Symlin?
Symlin is an analog chemical that closely mimics the action of an endogenous human hormone produced by the islet cells called amylin (yes, the same name taken by Symlin's manufacturer). The first time I read about amylin was in the mid-1990s when I picked up a heavy medical tome from my college library and looked up "islet cells". That book mentioned amylin as something that was produced by the islet cells, but did not give me any insight as to what amylin did or why it was important to the human body. At the time, I was a newly diagnosed Type 1 and had a lot more on my plate to get used to, so I didn't give it much thought. That was also about the time Amylin began work on bringing Symlin to market, and in 2005 Symlin became only the second drug ever approved for the treatment of Type 1 diabetes (the first of course, being insulin).
Amylin is secreted by the islet cells along with insulin in a roughly 100:1 ratio of insulin to amylin, as part of a normal human body's reaction to food. It does not and cannot lower blood glucose on its own, but accomplishes the same through a variety of indirect means, including:
-Suppression of appetite
-Signaling the liver to stop releasing glycogen (stored sugars) into the bloodstream
-Slowing the rate at which your stomach empties, thereby significantly reducing or eliminating altogether post-meal spikes in blood glucose
-Increasing the potency of insulin
You might have guessed that eating less food and needing less insulin to cover meals might result in significant weight loss. This is true. Symlin is truly remarkable in this aspect, and in fact Amylin is in phase II clinical trials now with a combination drug treatment of Symlin and another hormone called leptin, designed specifically to treat obesity. I lost about 30lbs. on Symlin over the course of less than three months, without any other changes to my diet or exercise routine.
Human amylin can be quite toxic in that it promotes the formation of amyloid plaques throughout the body. These plaques are implicated in a host of nasty diseases, including Alzheimer's, Parkinson's disease, and rheumatoid arthritis. For this reason, Amylin used parts of the rat version of amylin in creating Symlin, so that it retains its positive effects in humans without the toxicity problems.
Is Symlin right for me?
Are you a human being? Do you eat food? Then Symlin is probably right for you. However, going on Symlin requires diligent attention to your diabetes and can cause some serious problems if that is not your current strategy. If you already struggle with hypoglycemia then it would be best to work that problem out before starting on Symlin, as it is the most challenging aspect of Symlin therapy. If you have hypoglycemia unawareness, Symlin is probably not right for you. I recommend using Symlin in conjunction with a CGMS as it is much easier to deal with any potential hypoglycemia that way, but I and many others acclimated to Symlin without one so it is by no means necessary.
How is Symlin taken?
Symlin is taken by injection only, immediately before a meal. The literature says to use Symlin only with meals containing 25 grams or more of carbohydrate. I have found it beneficial to use Symlin before any substantial eating, whether or not I hit that magic number. For me "substantial eating" is any volume of food that meets or exceeds a couple of bites. So, I won't take my Symlin if I toss down a couple of crackers with cheese at a party, but anything more than that gets a jab.
It does come in a pen, like most forms of insulin, and as a pump user who hasn't used injections since 1997, I found this much more convenient than lugging around a kit with bottles and syringes. Unlike insulin, your Symlin dose will not change- it will be either 60mcg or 120mcg per injection, no matter how much you eat. There are two pens available- one that maxes out at 60mcg and one at 120mcg. The 60mcg pen can deliver doses in 15mcg increments from 15mcg up to 60mcg. The 120mcg pen can only deliver 60mcg or 120mcg per injection. I will discuss dosing in more detail in the next post, including how to acclimate to your full dose of 60 or 120, and how it reduces your meal-time insulin requirement.
Symlin cannot be mixed with insulin for injection, nor can it be infused with insulin in a pump. A few brave souls have hooked up a second pump to infuse Symlin, but I believe the pen and consistent dosages obviate the need for such an expensive and inconvenient method.
What are the negative side effects?
After you have acclimated to your full dose, there are surprisingly few, if any at all. I experience no negative side effects myself and I have been using Symlin since September of 2008. During acclimation, you may experience some mild to moderate nausea and gastric discomfort for a short while after eating. And while this is not a true side effect of the medication, I would be doing you a great disservice if I did not mention that the pH of Symlin is apparently rather low and it does not appear to be buffered much. So unlike insulin, which goes in painlessly, Symlin can sting a bit at doses at and above 60mcg. Some have mentioned they don't notice it at 60mcg, so your mileage may vary. I have in the past compared the 120mcg dose to injecting lemon juice but I am being a tad hyperbolic. Nevertheless, be prepared, but don't be scared. It is quite tolerable, especially for anyone used to the sharp snap of an infusion set or CGMS insertion.
I also use my abdomen almost exclusively, but I have noticed it stings far less in my leg or butt. Absorption does not appear to be effected by where I inject, so this may be a good way to mitigate the pain if that is an issue for you.
That's enough for my opener. Part 2 will cover acclimation in more detail, hypoglycemia issues, and meal bolus strategies. Part 3 is still a work in progress but thus far contains information on exercise, missing Symlin doses, potential train wrecks, and more. If you have any suggestions please send them my way. Thanks and good luck!