There are a number of different medications that can be used to treat ADHD, and each person may respond differently to each one. Some people may find that one medication is effective for a while but then stops working as well as it did at first. In this case, it may be necessary to switch to a different medication in order to continue seeing results. Other people may find that they need to try several different medications before finding one that works well for them. Still others may find that they never really respond well to medication and need to pursue other treatment options.
In general, switching ADHD medications is not considered to be harmful. However, it is important to work closely with a doctor or other qualified mental health professional when making any changes to your medication regimen. They can help you weigh the risks and benefits of changing medications and make sure that you are making the best decision for your individual needs.