I have not tried 6mp or azathioprine because my doctors were not sure it would help with such a severe flare. I also haven't been on pred; I think my GI tries to avoid it as much as possible. I am interested in Simponi, I think I will mention it to my doctor and see what he says.
Ok, here is a bit of an overview of meds just to sum up things (I must have missed it, but are you a Crohn's or UC patient? Also, are you located in the US or elsewhere?):
Pentasa: usually prescribed long-term, helps principally UC patients and some Crohn's patients. Not a powerful drug, but also not that many side effects. Today, often used in addition to other drugs, some docs have dropped it alltogether for Crohn's patients.
Flagyl, Cipro, other antibiotics: short term use to treat fistullas, abscesses, no long term use recommended. Doesn't really help with Crohn's long term.
Immunosuppressives (azathioprine, 6mp): used long term over years to get patients into remission by suppressing the white blood cell count to the normal lower range. One of the two current standard long term management approaches.
Biologics (remicade, humira, cimzia, simponi): statistically most effective use for long term Crohn's treatment. Sometimes used in combination with immunosuppressives which yields even higher results. Another drug which is a biologic which has not been mentioned before is natalizumab (tysabri) which had some problems in the past and was withdrawn for Crohn's use in Europe butis still used in the US if I am correct.
LDN: one smaller study showed the long term benefits of LDN for Crohn's. It has not beem approved for use in Crohn's or UC cases. Was developed to fight alcoholism.
Corticosteroids (prednisolone, budensonide): these are used mainly short term to fight inflammation (they can have serious side effects - statistically much, much more likely than the serious side effects of the other mentioned drugs avor - if used long term). Pred is more effective for Crohn's because it works on the whole intestine, it is also more dangerous. Budensonide (Entocort) works only well if the Crohn's is concentrated on the lower smaller intestine and upper colon.
Having said that I would not dismiss the use of aza or 6mp at this stage and depending where your inflammation is located would ask for pred for short term use.
P.s. I don't know much about Stelara, but here is a thread on it
http://www.crohnsforum.com/showthread.php?t=32002&highlight=Stelara&page=7 .