Hi Clairewelsh,   With the information you've given, I don't have enough to do a thorough search for  information to give you. You should work with your doctor and make sure you write everything down and keep track of the things you are told. If you don't think the doctor is working in your son's best interest, then you need to find another doctor. There are times when the wrong antibiotic is prescribed or it interacts with something else, and it can do damage rather than good.   If you can remember the name of the infection or condition I might be able to point you to some information. Take care. Please stay in touch and let us know how you and your son are doing!Vicki M