The first thing I�d advise in a project of this nature is to make sure you convey to the reader your impartiality. In other words, be careful that your data is not based upon too much of the bumf that drug companies tend to churn out based upon trials they have sponsored themselves. Sourcing your information from Wikipedia alone could land you in a whole lot of trouble for this reason plus the fact that Wikipedia is user editable.
Some of the best general academic resources for information like this include the latest edition of the BNF, Rx list and the electronic Medicines Compendium. The first is normally only accessible via uni servers and may need your ATHENS details but you could sign up for a trial or get hold of a hard-copy. The Rx list and eMC should be accessible from any PC. Here�s the links:
http://www.bnf.org/bnf/bnf/current/
http://www.rxlist.com/script/main/hp.asp
http://emc.medicines.org.uk/
Further, more detailed information is available from such sources as The Merck Index, Ingentaconnect, Scopus, ScienceDirect, EBSCO, Psychiatryonline etc. All of these titles require access from universities/colleges via ATHENS or alternatively, via ezproxy etc as they are subscription services designed for academic researchers and other experts only and not the general public.