The side effects of Prozac can be very dangerous. Although this is a drug supposed to help patients deal with depression and other emotional and mental issues, the medication can actually increase the frequency of suicidal thought. The problem is even more profound in children, because they are more likely to act out their feelings. In addition, Prozac can react adversely with other medications and cause users big problems. For example, Prozac and MAOIs can result in a dangerous build up of serotonin in the system. If this happens, users must go to the hospital until the levels of the chemical return to normal.