Final answer:
The patient administered metoclopramide (Reglan) should report tremors as an adverse effect, which could indicate tardive dyskinesia, a significant and potentially irreversible condition.
Step-by-step explanation:
When a patient is administered a dose of metoclopramide (Reglan) and complains of nausea, it's important for them to be aware of potential adverse effects. Among the potential side effects, the patient should report tremors to their healthcare provider. Tremors can indicate a more serious condition called tardive dyskinesia, which is a possible side effect of metoclopramide, affecting the nervous system and resulting in involuntary, repetitive body movements. Other side effects like constipation, double vision, and numbness in the fingers could also occur and should be reported, but tremors are particularly noteworthy due to their potentially irreversible nature if the drug is not discontinued promptly.