Final answer:
Adenosine is the medication that, if ordered, requires careful monitoring for asystole in a patient presenting with dizziness and shortness of breath.
Step-by-step explanation:
The medication that, if ordered, requires careful monitoring for asystole in a patient presenting with dizziness and shortness of breath is Adenosine. Adenosine is an antiarrhythmic medication that works by slowing down the electrical conduction in the heart. It is commonly used to convert certain types of abnormal heart rhythms back to normal sinus rhythm. However, asystole is a potential side effect of adenosine administration, so close monitoring of the patient's heart rhythm is necessary.