Sunday, July 27, 2014

A New Drug for Type 2 Diabetics

In normal people, insulin causes sugar to be taken up by cells, especially in muscle, liver, and fat.  But in Type 2 diabetics, insulin loses its effectiveness, and as a result too much sugar remains in the blood.  Most of the drugs currently used to treat diabetes improve cells’ ability to take up sugar from the bloodstream, thereby lowering the blood sugar level back toward normal.

Now there’s a new drug that works in an entirely different way.  Invokana was developed based on a basic knowledge of how the kidneys handle blood sugar.   Normally, all of the sugar that is filtered in the kidneys is reabsorbed back into the bloodstream; none is excreted in the urine.  It’s nature’s way of conserving energy (sugar).  The mechanism of sugar reabsorption involves sugar transport “pumps” (comprised of certain proteins) in cells of the renal tubules.   Invokana blocks those sugar transport pumps, so some of the some of the filtered sugar is not reabsorbed.   Instead, it is excreted from the body in the urine.  In diabetics (whose blood sugar is too high), that's a good thing, because it lowers the blood sugar level.

One of the potential side effects of Invokana is a slight loss of weight.  That makes sense when you think about it; sugar lost in the urine equals calories lost.  In diabetics who are also overweight, that could be a good thing.   But I see a real danger here; what if people are led believe that Invokana would work as a diet pill (“just pee those extra calories out!”) and a black market develops for it?

I hope that doesn’t happen.  There’s no data yet to prove that Invokana would result in enough weight loss to make a dieter happy.  More importantly, in a person with a normal blood sugar level to begin with, Invokana might lower blood sugar to dangerously low levels.   Unfortunately, people are willing to believe some pretty crazy things when marketers (black-marketers or otherwise) give them just a grain of truth.

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