August 11, 1999
Medications: Pills for Diabetes
Question from Nashua, New Hampshire, USA:
I was diagnosed with Type 1 diabetes 15 years ago. No complications as of yet. I am an RN and recently a drug company representative gave us a little in-service on metformin [a pill for Type 2 diabetes]. The “big seller” this time was that metformin is now okay for Type 2’s on insulin, and how Type 2’s end up needing less insulin with the addition of metformin. Sounds logical. So I inquired about the average weight loss seen with the Type 2’s and all of a sudden he say’s “I have been a Type 1 diabetic for 14 years and I take metformin and don’t need as much insulin. I have lost a couple of pounds since starting the medicine.”
This drug rep. was not overweight; maybe could stand to lose 10-15 pounds. He stated that he was on 4 shots a day. His daily requirements had been significantly reduced. He has been taking the medication “off label” for a while now and he thinks it really helps.
I am on an insulin pump. My last A1c 5.3. I realize this is good control. I weigh about 120 pounds and I’m 5’2″. I used to run about 30 miles a week. My average daily insulin (Humalog) intake when I was running was between 19-26 units/day. I developed an annoying tendonitis and had to stop running. I have continued to exercise, but I am now taking between 25-35 units/day now. My intake is about the same — I’m just not burning the 600-800 calories per workout anymore. I have gained about 10 pounds since having to stop jogging.
Even though I realize that 25-35 units/day is not a whole lot of insulin, I feel as though it is for me. I have been seriously thinking about trying metformin. Does metformin act on the exogenous insulin receptors as well? I am not worried so much about the usual side effects from initially starting the drug (GI stuff). My concern is will this drug make my insulin receptors less likely to act on its own when/if I decide to go off it?
I know that insulin is a great hormone (well, the only hormone!) for bringing down blood glucoses, but I also know that the hormone has annoying tendencies as well (lipoprotein lipase). It seems that we would all be better off if we used less insulin — diabetic or not! Please understand, I am notketoacidosis! And I am not saying that Type 1’s should use less insulin when their blood glucoses are high. I am simply saying that studies have shown that with less insulin on board, general health seems to be better — lipid levels, weight. So can metformin help me?
Thanks — hope this message wasn’t too long winded. I just didn’t want anyone to misunderstand my question.
You pose some interesting questions but I feel that you have been the victim of pharmaceutical company “spin”. Let’s review: Metformin lowers blood glucose primarily by suppressing hepatic gluconeogenesis. In layman’s terms, this means the glucose that your liver manufactures, mostly in the early morning hours. This is why the fasting blood glucose can be helped by taking metformin, if you are a type 2. For people with type 2 diabetes, the liver glucose that accounts for the level of the fasting blood glucose is about 1/2 glucose from liver storage and about 1/2 new glucose manufactured by the liver. If you don’t have type 2, the glucose released from the liver is mostly stored glucose and metformin won’t help. If the drug rep lost weight as a result of the metformin, it was probably because of nausea caused as a side effect of the drug: not a good way to lose weight!
Hopefully you can see in this discussion that this drug is not for you. It can be very helpful for people with type 2 diabetes who are insulin resistant (their liver cells are also insulin resistant and don’t know to turn off the glucose). For a type 1, this drug is not only not helpful, it could be quite harmful. As to saying that insulin causes dyslipidemia (problems with blood fats), that is not true. Insulin lowers triglycerides in many individuals. The condition of insulin resistance with it’s accompanying disorders of high blood pressure and abnormal lipids has an effect of high insulin levels but it has not been shown that it is the insulin levels that cause the higher risk for heart disease. In fact in the The United Kingdom Prospective Diabetes Study, patients on insulin, sulfonylurea and metformin had improved outcomes with heart disease, leading many to the conclusion that it is the high blood glucose and blood pressure that are causing the heart disease. You are in excellent control; hopefully you will be able to find another way to lose the few extra pounds without experimenting with metformin.