DIURETICS ARE COMMONLY USED IN the neonatal intensive care unit (NICU) to remove excess extracellular fluid secondary to various diseases, such as chronic lung disease (CLD) and congestive heart failure (CHF). Diuretics are among the most used of all medications across age groups. They are also among the most abused medications, with the potential for many untoward side effects.3,4Thus, NICU nurses must understand their appropriate use, their possible consequences, and the monitoring required when using them. Furosemide and chlorothiazide have been reviewed previously (see Neonatal Network, 1991, 9(7): 65–67, and 1993, 12(7): 69–70, respectively). This column focuses on spironolactone use.