Baytril and clavamox are quite a common combination used for dogs at the same time and thewre is very rarely a problem with it. If your dog is suffering from possible pneumonia this is a good combination to tackle the most likely causes and in an older dog with this problem it is necessary to try to get on top of it as quickly as possible to get the best chance of success.
If you notice any side effects such as vomitting or diarrhoea with the tablets then stop giving them and give your vet a call. Don't worry if your dog is drinking more than normal and peeing more - this is the effect of the lasix.
I hope this helps,
Thanks, XXXXX XXXXX and trust my Doc implicitly, but it always helps to bounce it off another in the field.