A recent New York times piece by Gina Kolata summarizes some recent writing in medical journals bemoaning the proliferation of side effects in drug labels.

From the FDA:

"extensive lists of rare and minor adverse events for which there are no data to support a causal relationship" are not useful.

I don't know exactly what the FDA is means by "data to support a causal relationship", but considering that it takes millions of dollars of randomized experimentation...