@becsbuddy - Becky, I had Cytoxan as one of the drugs in chemo for breast cancer. I was first given tablets, but I did not tolerate it- sensitive stomach- and I was switched to infusions, better tolerated. I was also taking Zofran for nausea.
For my first autoimmune disease some years ago, I was given injections of methotrexate- another one of my chemo drugs. Nausea, fatigue mostly.
When you start Cytoxan you will be monitored with blood tests to stay safe. I always think that I’m not committed to anything forever. If you don’t tolerate it well, there are other treatments. Good luck!