Final answer:
The nurse should discontinue the infusion, replace the pump with a functioning one, and restart the infusion.
Step-by-step explanation:
When a nurse is caring for a patient receiving intravenous drug therapy via an infusion pump, and the pump continues to sound an alarm, there are specific actions that should be taken. The correct course of action for the nurse to follow is to discontinue the infusion, replace the pump with a functioning one and restart the infusion. It is important to label the broken pump and place it in a designated area for broken equipment.