How can street drugs affect a person if (s)he's on antidepressants?

The combination can kill you; physically, if not mentally. You cannot be certain of the purity of street drugs, either. You could find yourself in a grave, in gaol, or in Bedlam. Stay away from them.

Combinations like that can kill somebody! Cocaine and ecstasy are hardcore drugs and combining them with an antidepressant can lead to some major consequences.

Don't listen to all these people telling you how horrible you are for asking a question about this. If you're smart about drugs, and you stay responsible when you use (it's extremely possible, as long as you have a little willpower) you will have a great time, and live to see another day. That said, mixing Prozac and ecstasy is a completely bad idea. Prozac is what's called an SSRI, it works by messing with the serotonin transmitters in your brain to make you feel not depressed. First, I'd suggest getting off of it completely. SSRIs are horrible drugs, and they don't do anything but mess with your head. Stop taking your prozac for at least a month, if not a little bit longer, before you roll. That gives your brain time to regroup and get back to working normally. If you take ecstasy while you're on SSRIs, you will not only not feel any effects, you risk what's called Serotonin Syndrome, which can be very fatal. Drugs can give you the best and most intense moments of your life, but it's also a double-edged sword. It's great that you're asking these kinds of questions because that's the first step to responsible drug use. Stay safe and enjoy the good times ahead.

your asking a question about doing illegal drugs. You sound like a winner to me. good luck in down-hill life.