The case of The Evil Scale - solution

The answer: choice number "3." Harry's weight gain was most likely due to the Avandia.

Avandia (rosiglitazone) and Actos (pioglitazone) are members of a new class of oral hypoglycemic agents (that is; pills to lower blood sugar) called TZD's. They can be quite effective, but they often do lead to some weight gain. Note that not all weight gain is the same. Whereas some pills like glyburide (Diabeta) often lead to extra fat, TZD's may lead to weight gain due to excess fluid retention (other reasons are also possible - this is still under investigation). Some people get swollen ankles and some people, if their heart function is not good, can actually go into heart failure. Most people do not have much of a problem with fluid retention on TZD therapy.

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.