A client who is newly diagnosed with diabetes insipidus (DI) is receiving a synthetic vasopressin intravenously. Which side effect of vasopressin reported by the client should the nurse report to the healthcare provider?

A. Polyuria: Polyuria, or increased urine output, is typically a symptom of diabetes insipidus (DI) rather than a side effect of vasopressin. Vasopressin is used to treat DI by reducing urine output, so the presence of polyuria might indicate that the medication is not effective or that the dosage needs adjustment. B. Low urine specific gravity: Low urine specific gravity is also a symptom of DI, reflecting the kidneys' inability to concentrate urine. With the administration of vasopressin, one would expect an improvement in urine concentration and specific gravity, so low urine specific gravity could indicate that the medication is not effectively managing the condition. C. Polydipsia: Polydipsia, or excessive thirst, is a common symptom of DI. While it may improve with effective vasopressin treatment, its presence alone is not usually an immediate concern requiring healthcare provider notification unless it significantly worsens or is accompanied by other symptoms. D. Worsening headache: A worsening headache could be a sign of water intoxication or hyponatremia, which can occur if vasopressin causes excessive water retention. This is a serious side effect that requires immediate attention, as it could indicate complications related to vasopressin therapy. The healthcare provider should be notified to assess and address any potential adverse effects of the treatment.