Methods of treating bendamustine responsive conditions in patients having fluid and/or sodium intake restrictions are disclosed. The methods include identifying patients having such restrictions and in need of bendamustine, and then administering thereto a bendamustine-containing composition in a volume of about 120 ml or less intravenously over a period of about 15 minutes or less. The smaller volumes and reduced sodium load as compared to currently known methods of treatment minimize cardiac and/or renal stress in patients having diseases such as congestive heart failure or renal disease.