I don't know what size town you live in, but if a med suddenly stops working or causes issues and a prescribing doctor says that he has heard of similar stories, then I would be asking at my pharmacy to look into it and see if there has been a recall or possibly even initiate a recall. IIRC for example all CVS pharmacies get their stuff from specific suppliers so it might even be already known that a certain lot or lots have issues and probably should have been pulled from sale. Imported drugs are supposed to be tested before being released for sale, but doo doo still happens.