When the Nurse Brings in the Next Dose of a Drug

When the nurse brings in the next dose of a drug that a patient first received 6 hours ago,the patient reports a "pounding" heart rate ever since taking the last dose.What is the nurse's best first action?

A) Document the report as the only action.
B) Check the patient's vital signs for changes.
C) Hold the dose and notify the prescriber immediately.
D) Reassure the patient that this is an expected response to the drug.