My Longhair domestic cat's had a skin problem on the back of her back leg. Unaffected by a shot of antibiotic (Convenia) given 8/20, I returned to the vet 9/11. At that point vet gave same antibiotic shot, a steroid injection (Depo-Medrol) and Synotic to apply locally 2X's/day. Additionally, a course of Metronidazole was started 9/11 and completed 9/15. The poor animal has had diarrhea since 9/11. The administrator of the vet clinic insists they've used Synotic on cats before without deleterious effect but they may not be fully aware of the consequences.