My teenage son has had diarrhea, vomiting and fever for 12 hours. Our GP has prescribed a 3 day dose of Azithromycin in case it is a bacterial infection? I'm just wondering whether this would actually make his symptoms worse? (Doesn't Azithromycin cause diarrhea as a side effect) and worried about it being marked as a black-box medicine. (Something related to arrhythmias?) so reluctant to give it to him. Any advice please?