A nurse is caring for a client who has diabetes insipidus and is receiving vasopressin. The nurse should identify which of the following findings as an indication that the medication is effective?

A. Vasopressin may actually cause a slight increase in blood pressure due to its vasoconstrictive effects, not a decrease. B. Vasopressin does not affect blood glucose levels. C. A decrease in urine specific gravity would indicate more dilute urine, which suggests ineffective treatment in diabetes insipidus. D. Diabetes insipidus is characterized by excessive urine output due to insufficient antidiuretic hormone (ADH). Vasopressin is a synthetic ADH that reduces urine output, so a decrease in urine output indicates the medication is effective.