April 15, 2008

The Limitations of Lantus

There's a common error revealed by many emails I get as well as what I see posted on discussion boards. It has to do with the failure of medical staff to explain to patients for whom Lantus is prescribed what it is that Lantus does and what it is that Lantus cannot do.

Lantus is a basal insulin. Basal insulin are slow long-acting insulins that attempt to mimic a specific function of the healthy beta cell. Normal people's beta cells secrete tiny pulses of insulin every couple minutes throughout the day and night. These pulses allow healthy cells to take in blood sugar and use it any time they need to. This slow steady release of tiny bits of insulin is called Basal Insulin Release. It is a failed basal insulin Release that Lantus attempts to replace.

But basal insulin production is a completely separate function from the much more powerful insulin release that happens when you eat foods that contain carbohydrates. That is because the influx of a large amount of carbohydrate into the digestive system stimulates two more insulin releases--first phase and second phase insulin release. These fast, large insulin releases are much more powerful than the tiny pulses of insulin produced during basal insulin release.

The problem patients run into when they are prescribed Lantus is that they do not understand that there are these different kinds of insulin release and assume that if they are injecting insulin to replace the insulin their bodies no longer make, these injections should be enough to give them normal blood sugars.

But if Lantus is what they are injecting, it will be impossible for most people with Type 2 to get normal blood sugars when they eat any significant amount of carbohydrate. Though they inject a large dose of Lantus, that Lantus will be absorbed very slowly over a period of anywhere from 22 hours to three days. So at any given moment only a very small amount of Lantus is active in the blood stream. That is why Lantus only lowers fasting blood sugar.

Though it makes sense that if you lower your fasting blood sugar, the amount your blood sugar rises after eating a meal should be lower too, in reality, no matter how low your fasting blood sugar might be, thanks to Lantus, if you eat 60 grams of carbohydrate at one time--whether it be from "healthy" whole grains or any other starchy or sugary food, your post-meal blood sugar will still rise 150-300 mg/dl.

The exact extent of that rise depends on your weight and how many beta cells remain alive. For a person who weighs 140 lbs, 2 grams of carbohydrate will raise blood sugar 10 mg/dl. For a person who weighs 280 lbs, the same 2 grams will raise blood sugar 5 mg/dl.

Whatever residual insulin secretory function your beta cells have left will limit the rise you actually see after consuming carbohydrates, but because doctors delay prescribing any kind of insulin until a person's blood sugar control has deteriorated to where most beta cells are likely to be dead, by the time a person with Type 2 diabetes starts Lantus, it's very likely those post-meal spikes caused by eating carbohydrates will be very high indeed.

But because Lantus is absorbed so very slowly and because only small amounts of insulin are active in the body at any one time, Lantus insulin will has no effect on those high post-meal spikes at all. It's too slow and too weak.

So even if a person is taking enough Lantus to get a normal fasting blood sugar level of 85 mg/dl (which most aren't), after each high carbohydrate meal their blood sugar will be soaring well above 200 or even 400 mg/dl. Blood sugars that high damage nerves, capillaries, retinas, and kidneys and cause amputation, blindness and kidney failure.

So no matter what decrease there might be in their A1c after adding Lantus to their daily regimen, the person with Type 2 who takes Lantus and continues to eat a high carbohydrate diet is heading for a very ugly future.

The only insulins that can lower post-meal blood sugars are the fast acting insulins, Regular Human Insulin (Humulin or Novalin R), Humalog, Novolog, and Apidra. Those insulins must be dosed very carefully to match the amount of carbohydrate in each meal or they won't be effective either.

Unfortunately, it takes time to educate patients about how to match insulin to food. Time doctors don't want to spend on patients because it is very poorly reimbursed by insurers. So most people with Type 2 Diabetes do not have access to the well-trained diabetes educators who could teach them how to use fast acting insulin and match it with their food. Instead doctors turn them over to the care of a nurse who may have learned all she knows about insulin 20 years ago and whose main concern when she faces a patient is to avoid hypos by keeping the doses of insulin that patient uses low enough that the patient rarely sees a blood sugar lower than 180 mg/dl.

The sad truth about insulin is that it takes intelligence and study to use it correctly and most doctors don't credit their patients which having either the ability or motivation to learn how to use this powerful, life-changing drug correctly.

If you are willing to put in the time to learn to use insulin correctly, you can get very good control. Read these books: Dr. Bernstein's Diabetes Solution by Dr. Richard K. Bernstein, John Walsh's Using Insulin, and Gary Scheiner's Think Like a Pancreas. Each of these books takes a different approach to both diet and dosing, but reading them all should give you some insight into how to approach using insulin so that you can tailor your own dose to your own diet and exercise level.

After you've read these books and have a better idea of what is involved in using fast acting insulin, if you think you need fast acting insulin, keep at your doctor until he prescribes it for you or refers you to an endocrinologist who will.

If your doctor does not send you to a competent diabetes educator, or if after reading these books, and doing what the diabetes nurse suggests you are still seeing dangerously high blood sugars, visit one of the support communities you'll find online like Tudiabetes.com, diabetesdaily.com or diabetesforums.com and discuss your situation with the people there who use insulin to get excellent control.

Even though you are a Type 2, you may find that Type 1s have a lot to teach you because they generally get much better diabetes education than do any Type 2s. If you listen carefully to people using insulin whose control is excellent, read the suggested books and pay attention to what their authors are trying to tell you, and cut back on your carbs as much as possible, you should be able to get your blood sugars back into control. Many of us have done it.


Laura Williams said...

I have to be sceptical about your statement "For a person who weighs 140 lbs, 2 grams of carbohydrate will raise blood sugar 10 mg/dl. For a person who weighs 280 lbs, the same 2 grams will raise blood sugar 5 mg/dl."

Is there really that direct a tie in to weight and blood sugar reaction to food? Is there a particular study you're referencing there?

In my experience it's not that straightforward. Of course, time frames make a big difference, how long it takes to raise that 5 or 10mg/dl, but I think the amount of beta cells, the level of insulin resistance the amount of sugar being dumped by the liver have big effects.

I guess I disagree with the implication that losing weight will increase your blood sugar levels. Isn't losing weight supposed to reduce insulin resistance?

Jenny said...


Yes, there is a direct tie to how much a given amount of carbohydrate will raise blood sugar in the absense of insulin. Dr. Bernstein documents this in his book when discussing how much glucose is needed to counteract a hypo. His calculation works perfectly for me.

Obviously, whether a person is still making insulin will damp down the height of a spike, but as I explained in the blog post, by the time most people are put on insulin they have burnt out a lot of beta cells or are extremely insulin resistant. I hear from people all the time who are "on insulin" but spending much of the day over 200 mg/dl.

Re the effect of losing weight, don't confuse the issue of how high ingested glucose will raise blood sugar with how effective insulin will be in bringing it down.

How high carb raises blood sugar in the absence of insulin is dependent on body size. How effectively insulin will lower blood sugar is dependent on IR which can be decreased, in some people, by weight loss.

This is one reason why large men are able to lose a lot more weight eating a lot more carbs when they go on low carb diets. Also why some people with Type 2 are able to get excellent blood sugars while eating an amount of carbs that would be toxic for a smaller person.

The diet books ignore this issue, but I have certainly seen it play out in discussions. The people who can eat 50 g of carb and lose weight and get normal blood sugars think those who have to eat 12 g to get the same effect are nuts, and vice versa.

Anonymous said...

Jenny - I maintain with my nightly shot of Lantus, and the 0-2 times a day supplement of Regular insulin. This is obviously the classic case of the exception proves (actually the proper modern word is 'tests') the rule. And you can claim credit! I started insulin the third morning after my fasting FBGs were above 126. I wish I had started a couple of years earlier. I have enough pancreas function left to make this possible. Thanks - RobLL

The Old Man and His Dog said...

It's like you were reading my mind. This answers the question I had with my Lantus regiment. My only problem was after a meal of more than 20 carbs. Now I know why. Think I'll still try to stay below 20 per meal, but supplement with regular insulin if I'll be eating more than 20 on occasion. It's beyond me why my Dr. or diabetes educator didn't explain this to me when I started on Lantus. They knew how serious I was about getting to normal BS and also saw all my records neat an orderly I was. That I was fully competent in handling this and fine tuning everything to reach my goals. Blows my mind. Thanks again.

Jenny said...

Doctors don't explain this because many of them don't understand it. The drug reps tell them that lantus is the insulin they should start patients on, so they do.

But family doctors don't get much training in diabetes care and if they were trained in the 1980s to mid-1990s they may have never been taught about basal/bolus regimens.

The Old Man and His Dog said...

I hear ya, but this was my new endo and she's fairly young. Looks to be in her late 20's, freshly graduated, not a GP. She's the same one that tried to get me on statins and I showed her the article you forwarded. That's the last time I heard about the statins. Actually I think she's one that actually appreciates the info. Much more receptive than the other Dr's I've seen. Like you said, she just doesn't get the same info from the beautiful people(drug reps).

Anonymous said...

I am always shocked about how some T1 and T2 abuse insulin. I have heard many people say that yes, you can eat whatever you want in whatever quantity and all you have to do in increase the amount of insulin you use.

I personally think this is abusing insulin and refusing to take the necessary actions that will help manage diabetes beter.

I am not suggesting that people should not have the occasional sweet or go beyond thier carb intakes once in a while but it should not become an everyday habit.

What's your take on this?

Unknown said...

T o anonymous. I think (although I do not practice this) people should use their insulin to their own discretion. Its a disease that is very complicated. Its not like insulin causes a high. So if someone can afford and feels happy using their insulin whenever to eat whatever thats their life choice. I dont like how u used the word "abuse their insulin", if there were no diabetes then their body would make insulin as needed. Insulin replacement is there for a HAPPY Fulfilling life.