Like it was said before, steroids and 6mp, imuran, etc. are considered "more safe" because they have a longer history of clinical use and the side-effects or poor outcomes are well established. TNF blockers are new, less understood, and we have no idea what the long-term effects will be. When you decide what medication to take, there is a cost-benefit analysis. With the TNF blockers you can't really make an informed decision because part of the "cost" equation is still missing.
TNF blockers could also be considered more severe because (1) they require infusion or injection, versus oral (2) you can develop serum sickness, infusion reaction, lups-like symptoms or full-blown lupus, a fatal infection, cancer, and so on, and (3) cost is MUCH higher.
Some doctors are now advocating a "top-down" approach where they start newer Crohn's patients on a TNF-blocker (and possibly immunosuppressants as well) to establish a more lasting remission, skipping over the 5-ASA's or immunosuppressants by themselves. This may be your doctor's line of thought.
July 2007 Drug-Induced Liver Injury
January 2008 Crohn's Ileitis
Currently trying... Enteral Nutrition, Flax Oil, VSL#3, Folic Acid, Vitamin E