Side effects are problems that occur when treatment goes beyond the desired effect or problems that occur in addition to the desired therapeutic effect.
When side effects of necessary medication are severe, sometimes a second medication, lifestyle change, dietary change, or other measure may help to minimize them. Drug manufacturers are required to list all known side effects of their products.
Fatigue, nausea, vomiting, decreased blood cell counts, hair loss, and mouth sores are instances of side effects of cancer treatment that occur in addition to the desired therapeutic effect. A hemorrhage from the use of too much anticoagulant (such as heparin) is a side effect caused by treatment going beyond the desired effect. As with all drugs, some people react badly to antidepressants, while side effects can seem quite mild in others.
The irony here of course is that, helpful as antidepressants may be for some people at some times, these side effects can be very depressing in themselves.
Because no one antidepressant has been proven to be any more effective than any other, the choice of which drug to prescribe often rests on their different side...