A nurse is caring for a client who is receiving high-dose metoclopramide. The nurse should monitor the client for which of the following adverse effects?

The correct answer is B: Tardive dyskinesia. High-dose metoclopramide can lead to this serious adverse effect, characterized by involuntary, repetitive movements. This is due to prolonged use of the medication affecting dopamine receptors in the brain. Dry cough (A), black stools (C), and oral candidiasis (D) are not typically associated with metoclopramide use. Monitoring for tardive dyskinesia is crucial as it can be irreversible, making it the priority adverse effect to watch for in this scenario.