You will receive rituximab through a needle in your vein on Day 2. The first infusion may take up to 8 hours. For every dose of rituximab after that, the infusion may take 2-4 hours. The length of the infusion time depends on whether you have any reactions to the infusion. The dose level of rituximab may be increased for Cycles 2-6 as well. The drugs Tylenol (acetaminophen) and Benadryl (diphenhydramine hydrochloride) will be given before each dose of rituximab. This will be done to decrease the risk of side effects. If side effects do occur during rituximab treatment, the drug may have to be stopped until the side effects go away and then restarted, so your time in the outpatient area may be longer if that occurs.