Anoushka,
There are different medications out there for depression. Sometimes a person has to go through several before they find the one that is tolerable. Unfortunately, it takes several weeks to see the effects of an antidepressant. Your friend needs to hang in there on the drug issue - talk to his pdoc about the intolerable side effects.
If he's suicidal - call 911, the community crisis line, on the home page of this wed site, on the right hand side is a heading "feeling suicidal? Read this first". It has alot of good information in it and reasons not to - you could print it out, familiarize yourself with it, get him to read it and talk with your friend. It might be enough to get him to talk to a professional. That is what someone who is considering that needs. Also, if he doesn't have a psychologist, might I recommend that he finds one. Pdoc's usually don't do alot of counseling, they handle meds. Psychologists - therapists do the rest.
Good Luck - Anne