A nurse is preparing to administer a client's antihypertensive medication. When using clinical judgment, which of the following findings indicates the nurse should further assess the client before administering medication?

A. Difficulty sleeping is not directly related to the safe administration of antihypertensive medication and does not require immediate assessment. B. Consuming 60% of breakfast is within normal limits and does not affect the decision to administer blood pressure medication. C. A urine output of 400 mL over 8 hours is within the expected range and does not indicate renal compromise that would contraindicate the medication. D. Dizziness upon ambulation may indicate hypotension. Administering an antihypertensive could worsen the client's condition, so further assessment of blood pressure is necessary before proceeding.