Final answer:
The nurse should hold the medication and contact the healthcare provider if the patient complains of dizziness.
Step-by-step explanation:
When administering a calcium channel blocker, such as diltiazem (Cardizem), the nurse should hold the medication and contact the healthcare provider if the patient complains of dizziness. Complaints of dizziness can be an indication of low blood pressure or bradycardia, which are potential side effects of calcium channel blockers. Therefore, it is important to assess the patient's blood pressure and heart rate before administering the medication, and if any symptoms of low blood pressure or bradycardia are present, the healthcare provider should be consulted.