I just finished up chemo with my cat Kitty. She had mast cell cancer in her intestines and spleen. Kitty got 2 kinds of chemo: an IV chemo called Vinblastine and a pill form called CCNU. Kitty had very few side effects. No side effects with the pill form at all. She would get her chemo every other Wednesday and 4-5 days after the first vinblastine she acted like she felt bad. She vomited once, she didn't have much of an appetite, and she just wanted to sit in her chair all day. This only lasted about a day and a half. I took her to the vet and her blood test showed that her blood count was low. She took some antibiotics and was fine. After that, she stayed on antibiotics throughout chemo and the vinblastine was weakened a little and we had no more problems.
Kitty also has had probably 4-5 ultrasounds since we started down this road. She is so wiggly that they have to mildly sedate her to do it (she also has to have mild sedation to get the IV chemo). She has not acted like it bothered her.