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) Low urine specific gravity: This finding is expected in a client with diabetes insipidus, as the condition is characterized by the excretion of dilute urine. A low urine specific gravity indicates the kidneys are not concentrating urine effectively, which is consistent with DI. B) Polydipsia: Increased thirst (polydipsia) is a common symptom of diabetes insipidus due to the excessive loss of water. While it can be bothersome, it is not an alarming side effect of vasopressin treatment. C) Polyuria: Similar to polydipsia, polyuria (excessive urination) is a hallmark of diabetes insipidus. While the goal of vasopressin therapy is to reduce urine output, polyuria alone does not indicate an adverse reaction that requires reporting. D) Worsening headache: This symptom is concerning and should be reported to the healthcare provider. Headaches may indicate water retention or potential complications such as hyponatremia (low sodium levels), especially if vasopressin is leading to increased fluid retention. This could necessitate further evaluation and possible adjustment of treatment.