If there's not any improvement after 15 days, you likely won't see any and euthanasia is probably the kindest thing.
Though if you aren't seeing any improvement and you're faced with that decision, you may want to consider giving the azithromycin a try 30-50mg/kg, once a day). If it's going to work at all, it will happen pretty quickly. Significant improvement in 3-4 days is my experience with it. My rabbits ended up having to be on the higher dose of 50mg/kg and for an extended length of time, but it knocked the infection down very quickly and cleared it up completely after the course was completed.
If your rabbit is deteriorating significantly, you may want to consider giving it a try sooner rather than later. Even though there are more side effect risks with its use, at some point it becomes worth the risk to me.
Though if you aren't seeing any improvement and you're faced with that decision, you may want to consider giving the azithromycin a try 30-50mg/kg, once a day). If it's going to work at all, it will happen pretty quickly. Significant improvement in 3-4 days is my experience with it. My rabbits ended up having to be on the higher dose of 50mg/kg and for an extended length of time, but it knocked the infection down very quickly and cleared it up completely after the course was completed.
If your rabbit is deteriorating significantly, you may want to consider giving it a try sooner rather than later. Even though there are more side effect risks with its use, at some point it becomes worth the risk to me.