Antibiotics are not commonly used to treat ulcerative colitis, but they are used in certain circumstances. They may especially be used to treat such complications as a bowel perforation or toxic megacolon.
For more information about the use of antibiotics, I turned to UpToDate -- a trusted electronic reference used by doctors and patients. Read on for a summary of the evidence on the use of antibiotics to treat ulcerative colitis.
"Ulcerative colitis — Controlled trials of narrow spectrum antibiotics in ulcerative colitis have not demonstrated a consistent benefit. Thus they have little, if any, role in the treatment of active disease except possibly in patients with disease refractory to traditional medications or in those with fulminant colitis in whom they may help to avert a life-threatening infection. There is some developing evidence that broad spectrum rifaximin or combinations of antibiotics may have a role in treating ulcerative colitis, but more extensive studies need to confirm these preliminary results."
When antibiotics are used to treat an infection, it helps to know which bacteria are causing the infection because that knowledge helps the physician choose the type of antibiotic that will offer the most benefit. Narrow spectrum antibiotics are those that are only effective against certain strains of bacteria. Broad spectrum antibiotics are those that are effective against more types of bacteria.
Currently, there is not enough evidence to show that antibiotics would be useful in treating ulcerative colitis. Some studies may have shown a benefit, while others may have shown that there is no benefit. In the case of broad spectrum antibiotics, it is still an emerging idea, and there is currently not enough evidence to make a decision on effectiveness.
In some cases of severe ulcerative colitis, or when all other drug treatment has failed, antibiotics might be tried in order to help a patient who is very sick and does not have a lot of other good options. This all means that currently, antibiotics are not a type of drug that is likely to be used in the routine treatment of ulcerative colitis because they have not been proven to be effective.
Some researchers think there may be a connection between antibiotic use and the development of inflammatory bowel disease (IBD). This theory is yet unproven, with only a few studies and anecdotal evidence (personal observations or isolated cases) supporting it. People with IBD are sometimes counseled against the use of antibiotics when they are not clearly needed because of the risk of antibiotic-associated diarrhea. Want to learn more? See UpToDate's topic, "Patient information: Ulcerative colitis," for additional in-depth medical information.
Sartor RB. "Antibiotics for treatment of inflammatory bowel diseases." UpToDate. Accessed: July 2011.