Here's a reply from my secondary Rheumy at Stanfords. Typically cytoxan is used at 2 mg/kg orally for 3 months. Then for 3-6 months, the dose is lowered to 1.5mg/kg and imuran is added; then imuran is continued for 3 more months at 1.5-2mg/kg before then tapering over 6-12 months. The final taper regimen is highly variable and is really an art.

I believe this is the European regimen that he quotes. He always talks about it when he sees me.