A good starting point is MedlinePlus, which links to many other sites such as Cocaine abuse and Addiction.
For much more detailed and advanced research, you can search Pubmed. The search: cocaine "side effects" gets 208 hits. Very few of these will link to full text, unless you are onsite at a large medical library, because they are in VERY expensive medical journals. But the abstracts may give you useful information.

If you are near an academic library or have remote access via student ID, you can try Academic Search if your research is less advanced. The search: cocaine and side effects gets 131 hits in Academic Search. If you click "refine search" and limit to full text available, you still get 66 hits. Even limiting these further to "scholarly/peer reviewed" gets 53 hits. For even less technical information, for example if this is for a high school project, you can try Masterfile, which gets 45 hits for: cocaine and side effects. Note that in these Ebsco databases, you do not need double quotes for searching phrases (unlike in Google and many other web search engines, where a space means "AND").

As to the ingredients, the Office of National Drug Control Policy's Crack: Overview has general information on the difference between Crack and cocaine, for example: "Crack is cocaine that has not been neutralized by an acid to make the hydrochloride salt", and "Crack is cocaine that has been processed from cocaine hydrochloride to a free base for smoking. Crack cocaine is processed with ammonia or sodium bicarbonate (baking soda) and water.", which cites NIDA InfoFacts: Crack and Cocaine But for more detailed chemical composition, it seems best to use web directories such as Google, which gets sites such as Chemfinder. This gets a chemical formula if you search: cocaine, and it gives the structural formula as well, along with links to much more chemical and other information - including other names for the chemical. You can then try those other names in a Google Images search, to possible get better structural formulas. For example, under "Regulations...Information about this particular compound", it gives a very long chemical name, but also the shorter: Methylbenzoylepgonine, which gets 4 hits in images.google.com.

Jim Miller
jmiller2@umd.edu