I have had numerous treatments with Rituxan (rituxamab) with little or no side effects. The initial treatment in each series has given me mild, flu-like symptoms beginning at the end of the treatment (started at ~9 AM, 2-3 hours infusion time) and ending later that evening. Some persons receive an antihistamine (Benadryl) along with the treatment, as some (few) respond with allergic reactions, some quite serious, as did one friend of mine. Such allergic responses can be life threatening, as is the case with some persons' responses to bee stings. The addition of the Benadryl, for me, is actually the worst side effect, as it makes me dizzy and sleepy. I have dropped the Benadryl from my treatments. You may think this a favorable reaponse, as it makes you sleep through the infusion time. Rituxan is a pretty mild drug amongst the scheme of possible cancer drugs, although it is quite expensive.
Best wishes and God bless your efforts for good health and care.