My doc prescribed me some for a swelling on my lower spine and I only took 1. Once I found out that they could interfere with the course I am on I decided to try Ibuprofen first instead and it worked. Apparently some antibiotics do not interfere with the anabolic process, unfortunately I am not sure of their names. Some of the other bros may be able to help.

A few bros responded saying that they'd taken antibiotics during cycles and had not noticed any difference but I'd rather be safe than sorry. From what I can gather if you are on a course in a state of anabolism the antibiotics would raise your cortisone levels putting you in a catabolic state. As this has occured without your anabolic level dropping I suppose this means you would have even more chance of going catabolic whilst being off gear.

The only antibiotic that has been really shown to affect nitrogen retention is tetracycline, due to the fact that it inhibits bacterial protein synthesis. Although it is very specific to bacterial ribosomal subunits, there is obviously some cross reactivity with mammalian ribosomes. While negative nitrogen balance has been dmeonstrated with this drug, the same has been shown to occur with aspirin, and we know that all the users of the ephedrine/caffeine/aspirin combo are not wasting away.
The beta-lactams, such as the cillins and cephalosporins (cefixime, cefuroxime, etc.) are very specific to bacterial systems. They affect the formation of bacterial cell membranes, and have no cross-reactivity with human systems. This is the beauty of the beta-lactams, they pose very little threat to the host, while they are cidal to the bacteria.

None of the antibiotics are known to affect corticosteroid levels. The agricultural industry uses aureomycin as a GROWTH PROMOTENT for animals, because it allows for the animal to utilize more food for energy, by eliminating alot of intestinal bacteria that would otherwise digest the food and use it for themselves.

PRIMO, this is excellent advice and I think that everyone should do this after using a course of antibiotics. Probiotics usually contain Lactobacilli and Bifidobacteriae, which are looked upon as the "good" bacteria. They compete with, and suppress the levels of harmful bacteria.