Once a drug has FDA apprroval,there is basically no post approval surveillance of the drug .Almost all post market studies are performed by the drug companies themselves, not exactly unbiased sources of information. There is anarticle on post apprvoval testing of drugs in the June25,2007 edition of The New Yorker on pg 40.
In any case , the article does'nt suggest that supplemental steroids don't inhibit your own production of steroids.