Glad to hear Koa's infection is clearing up. Was there a cause ever determined? I would definitely check with your vet regarding the length of time he's supposed to be on it...3 weeks does seem awfully long. You may also want to be giving him yogurt (if you aren't already) to make sure the antibiotics don't wreak havoc on his digestive system. Plus, it will help keep the 'good bacteria' in his system.