This is not addiction. The body becomes better at getting rid of the medicine and more is needed for the same effect. However, addiction does not occur in children with cancer when they take narcotic medicines for pain. Some types of pain medicines can cause an upset stomach if taken between meals. To prevent stomach upset, try to take medicines with food.
Pain medicine can also cause side effects such as constipation, drowsiness, and nausea.
These side effects can be treated. You should always discuss these and other side effects with the health care team. If possible, it's better to prevent constipation before it occurs. It's important to keep track of your child's bowel movements, especially if your child has had problems with constipation in the past. If your child does not have a bowel movement after two or three days, notify the health care team.