Gentamicin Sulfate with Betamethasone Valerate

Question
I have a 4 year old male cat that had an abscessed sore on his tail.  The sore is open and draining.  The cat is eating and drinking water.  I used the above medication for my dog that recently had a sore on her tail.  Is this topical safe to use on a cat?

Answer
I am not sure it's safe but I do know that it will not help this abscess heal because a cat abscess is an entirely different deal then a sore on a dog's tail.
The bacteria alone is different and cat abscesses will only keep coming back if the cat isn't given oral antibiotics and doesn't have the abscess cleaned and flushed out.

It's just the nature of the beast and the way they grow a lot of really bad bacteria in their wounds.

So you need to call your vet and get him some oral medication as well as finding out about getting it cleaned up.