Depends on each country's law. In the US once you reach the age of majority, you have to tak responsibility for yourself. Some people lack capacity to make personal decisions, for instance due to a severe mental illness. Assuming this is not the case for you, you should be able to take control over your treatment and discuss alternative medications with your treatment provider. I am surprised you did not bring this up earlier, since an open communication is vital in a therapy, minor or not, your therapist/doctor should pay attention to your needs.