A nurse is assessing a client who is taking levothyroxine. The nurse should recognize that which of the following findings is a manifestation of levothyroxine overdose?

A. Hypoactive deep-tendon reflexes: Hypoactive reflexes are typically associated with hypothyroidism, not levothyroxine overdose. An overdose leads to symptoms of hyperthyroidism, which usually cause hyperactive or brisk reflexes rather than diminished responses. B. Constipation: Constipation is a common symptom of hypothyroidism due to slowed gastrointestinal motility. Levothyroxine overdose tends to increase metabolism, often resulting in diarrhea or increased bowel movements rather than constipation. C. Insomnia: Insomnia is a classic symptom of levothyroxine overdose caused by excessive thyroid hormone leading to increased metabolic rate and central nervous system stimulation. It reflects a hyperthyroid state and requires careful dose adjustment. D. Drowsiness: Drowsiness is more commonly associated with hypothyroidism or medication side effects that depress the central nervous system. Levothyroxine overdose typically causes symptoms of hyperactivity and nervousness, not sedation.