The case of the reluctant patient: solution

Nope, not choice number 4. I'd guess (ahem) my choice would be number 2.

Metformin is a great drug and can be used safely in the great majority of patients. There are, however, a select minority of patients for whom the risks of metformin outweigh the potential benefits. In particular, if one has significant kidney malfunction ("renal failure") then one should not be taking metformin because that unduly increases the risk of getting a potentially fatal side-effect termed "lactic acidosis." In Mrs. Lester's case, her metformin had to be stopped and hence, with the sugar-lowering effect of this drug no longer being available, it was a virtual certainty that her glucose levels would climb and would require another medication to be given. Since her sugars were already ten with metformin, once it was stopped her readings would likely climb above fifteen and additional pills would likely be very insufficient. Mrs. Lester is going to need insulin in order to keep her sugars in a safe range.

By the way, this is the format I use in my book (What Your Doctor Really Thinks).

Old cases of the month can be found here.