Side Effects are the undesired effects or issues that accompany the desired therapeutic effect. A small but illustrative example - Side effects of cancer treatment are Fatigue, Nausea, Hair Loss among others. Each and every medication has its own side effect.
In some cases the medications provided or recommended for a certain disease or defect may clash with that of the other medication and this may cause adverse side effects. It may also work the other way around when of a necessary medication are severe, sometimes a second medication, lifestyle change, dietary change, or other measure may help to minimize them.
There are some side effects that
tend to be rarely experienced, then there are thse that experienced for a short period of time, and then there are those that are not ever experienced by people who use the medications. The Manufacturing Company of that particular product needs to list out all the side effects so that the user of that particular product is completely aware of its side effects. For example, there is an warning issued to all smokers about the side effects of smoking on the pack of cigarettes.
The degree to which a person is likely to develop a particular side effect is based on studies on medical treatments, which show the rate or percentage of people who developed them. Depending on the ratio of people who developed them and people who survived , the calibration of intensity of the effects are considered. They also cause a hindrance to our lifestyle habits such as taking a morning walk or a jog , sleeping late at night and more.