Yet Another Problem with Januvia

UPDATE (April 2, 2013): Before you take Byetta, Victoza, Onglyza, or Januvia please read about the new research that shows that they, and probably all incretin drugs, cause severely abnormal cell growth in the pancreas and precancerous tumors. You'll find that information HERE.

Update (January, 2009) : A much more important problem with Januvia--that it promotes cancer by inhibiting a tumor suppressor gene researchers have called "the trigger for prostate cancer"--is discussed in this more recent blog post:

More Research Shows Januvia and Glinides Inhibit Tumor Suppressor Gene DPP-4. Posted Dec 8, 2008.

Original Post:


If you have had or might get melanoma, ovarian cancer, lung cancer or prostate cancer, please read the above post before making your decision about whether Januvia is for you.

Here is the original post that was posted 9/12/08:

I have been hearing from people about a new, and, to me, very troubling problem with Januvia. The problem is this: now that doctors have decided that all people recently diagnosed with Type 2 Diabetes should be put on Januvia, prescriptions for the combination drug Janumet, which is made up of both Januvia and Metformin, are becoming much more frequent as a first prescription for diabetes.

Metformin is a very safe drug that has been used safely for decades. The most recent follow up to the UKPDS study, the 20 year follow-up, which was just presented at the annual EASD conference found that at 20 years after the start of the study, "Patients treated with metformin had a 21% reduction in risk of any diabetes endpoint (P=0.01), a 30% reduction in risk of diabetes-related death (P=0.01), a 33% reduction in risk of MI (P=0.005), and a 27% reduction in risk of all cause mortality (P=0.002)."

Metformin is a very good drug for people with Type 2 diabetes because it decreases insulin resistance both at the muscles and at the liver. If the liver becomes insensitive to insulin it becomes deaf to the message that rising insulin levels in the bloodstream should give it, which is: "Glucose coming in from food I just ate." Thus the insulin resistant liver continues to dump glucose into the blood stream when there already is glucose there from a meal. This causes even higher blood sugars after a meal than would be due to the meal alone.

Metformin is also the only oral drug which has been shown consistently in studies to lower body weight rather than cause weight gain.

And its only side effects are mild--digestive system effects that, while they may be unpleasant, are not in anyway life-threatening or even permanent.

But here's the problem: Metformin does irritate stomach and intestinal linings, particularly when a person has just started taking it. That is why the Extended Release (ER) form is a much better prescription than the regular form, as it minimizes unpleasant digestive reactions.

Januvia, however, has a side effect that makes Metformin even harder to tolerate: by boosting GLP-1 it causes the lower stomach valve to remain shut. Without metformin in your body, this merely leads to a feeling of fullness and upper abdominal bloat. But if you have metformin in your system, it leads to much worse stomach distress.

When I was taking metformin ER and added Januvia, I found that the only way I could tolerate the two together was to take the Metformin several hours before I took the Januvia. Otherwise, my stomach was a mess for hours.

But the Janumet combination pill combines fast-acting metformin--the version that already causes a lot more nausea and diarrhea than the ER form--with Januvia, so it greatly exacerbates the metformin gastric side effects.

So what I am hearing from people recently diagnosed with diabetes is that after being put on Janumet they develop horrible stomach symptoms and their doctors switch them NOT to plain metformin ER, but to plain Januvia!

Thus they lose any drug action against insulin resistance, and are left with a drug, Januvia, that, if it is effective at all--which it often is not --raises their insulin levels without lowering their insulin resistance.

They also come away believing they could never tolerate Metformin, when, in fact, most could were they given the gentler ER form without the stomach-valve-closing drug Januvia.

Given the extremely positive effect that was seen in patients taking Metformin in the UKPDS f0llowup study--patients who had almost half the risk of heart attack at 20 years as patients who had taken sulfonylurea drugs which, like Januvia, stimulate insulin secretion, this trend is disturbing.

Most prescriptions for diabetes drugs are written by overworked primary care doctors (family practitioners or doctors trained in "internal medicine") who have very little training in diabetes care beyond what they are told by drug company salespeople. Sadly, the Merck salesforce has done such a snowjob on these family doctors that they are now moving their newly diagnosed patients to Januvia, an expensive, dangerous drug that has no impact on insulin resistance, and away from metformin.

If you are on Janumet and are having serious stomach or intestinal side effects explain to your doctor that these side effects are being worsened by Januvia and that you want to take Metformin ER ALONE, without any Januvia.

Also, if you do stop Januvia or Janumet, remember that it takes about two weeks for the Januvia to completely leave your system, and even after that, it may take another few weeks for your stomach value to begin operating properly again.

It took me more than a month after I stopped Januvia to recover normal stomach emptying.

And if your doctor tells you that you should keep taking Januvia rather than Metformin because Januvia will "rejuvenate" your beta cells, point out to him that this is drug company hyperbole that is not substantiated by any study that has looked at the beta cells of human beings. Instead, it depends on misinterpretation of HOMA calculations, which merely reflect the amount of insulin secreted and which in addition, recent research has shown to be highly inaccurate.

Januvia does not regrow beta cells. It merely stimulates them to produce more insulin at meal times. And if you are insulin resistant, eating a high carb diet, and not taking metformin, that additional insulin will do one thing for you: pack on additional weight.

You've been warned!