Final answer:
The nurse should instruct the patient to withhold Verapamil 48 hours prior to cardioversion in order to reduce the risk of complications during the procedure.
Step-by-step explanation:
The nurse should instruct the patient to withhold option 2: Verapamil 48 hours prior to cardioversion. Verapamil is a calcium channel blocker, which is a negative inotropic agent that decreases the strength of contraction and stroke volume. Withholding this medication prior to cardioversion reduces the risk of complications during the procedure.