A nurse inadvertently administered 160 mg of valsartan PO to a client who was scheduled to receive 80 mg. Which of the following actions is the priority for the nurse to take?

The correct answer is A: Evaluate the client for orthostatic hypotension. This is the priority because an overdose of valsartan can lead to a significant drop in blood pressure, potentially causing orthostatic hypotension. This can result in dizziness, lightheadedness, or even fainting when the client changes positions. Monitoring for this adverse effect is crucial to prevent any harm to the client. Checking for nasal congestion (B), obtaining laboratory results (C), and monitoring urine output (D) are important assessments but not the priority in this situation. Nasal congestion is not a common side effect of valsartan overdose. Laboratory results may be helpful in determining the extent of the overdose but do not address the immediate risk of orthostatic hypotension. Monitoring urine output is important for assessing kidney function but is not the priority when compared to the potential immediate risk of orthostatic hypotension.