I have been on steroids for 7 yrs. After 3 weeks at 25mg, they had shut down my adrenals and they have not recovered. I would try to use a normal tapering regime, get to 17mg and go into adrenal crisis (although no one realised at the time). Symptoms were bradycardia, low bp, trouble staying awake / conscious, nausea, confusion, chills. I would usually get a flare up as well, which was usually pericarditis or abdominal serositis, which would demand another bout of increased 'roids (upto 50mg per day).
Finally I described tapering symptoms, after my rheumy told me I wasn't being aggressive enough with the tapering, and she referred me to an endocrinolgist who did adrenal testing and diagnosed me with secondary adrenal insufficiency.
After 2 yrs, I am down to 7.5mg equiv dose, but on hysone (synthetic cortisol) as it is short acting and allows your body time without steroid, which assists with tapering. I manage increased inflammation with Naprosyn. I can't take imuran or methotrexate.
I now wean the equivalent of 0.5mg of pred, every 4-6 weeks, or when I feel my body can take it (usually when I stop sleeping). I'm still hoping that I can get lower, but I seem to be pretty unstable at this dose, so it might be pushing things too far.