There are lots of antibiotics available without a prescription. Tylan is only one of them. There are at least a few different ones available for farm animals, and a few available for aquarium fish. We can even get antibiotic ointment for humans.

However, what we can't get OTC is a culture that will tell us what sort of infection it is, and which antibiotics will help. Even broad-spectrum antibiotics like Baytril won't cure every infection, so if you want to give your snake the best chance of getting better ASAP, go to your vet and get a culture done. Then your vet will know which medicine to prescribe.

Here is a link to an old thread in which the possibility of treating a BP's RI with Tylan is discussed:
http://www.ball-pythons.net/forums/s...ighlight=tylan

I believe one person reported first hand success using Tylan to treat RI in a BP. Of course, we don't know for sure it was the Tylan that worked. Maybe the BP never had an RI. One time I managed to drop a drop of water right on the nose of one of my snakes. Immediately after, she whistling, popping, wheezing, and bubbling, just like they are supposed to with RIs, except her symptoms faded within a few hours. Something similar could have happened in this case and in others where snakes supposedly recover from RIs with no treatment or alternative treatments (or even those that get "properly" diagnosed and treated by a vet that is clueless about herps).

More importantly, several people pointed out problems with Tylan. Most of the 2nd hand info that was shared in that thread was about treating boas, not BPs. Maybe it is a very good RI treatment for boas, but that won't necessarily help a BP. Also, Tylan is apparently only effective against either gram negative or gram positive bacteria (don't remember which), but not both. If you don't know what kind of bacteria your BP has, you can't know if Tylan will be effective.

As far as your feeding question, an RI can definitely put your snake off feed. I recommend taking him to a vet, getting a culture done, and treating the RI. I wouldn't be surprised if once he is well again, he starts eating again.