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. Insomnia: Levothyroxine overdose can cause symptoms of hyperthyroidism, such as insomnia, restlessness, and anxiety, due to excessive thyroid hormone levels stimulating the nervous system. B. Constipation: Constipation is more commonly associated with hypothyroidism, not an overdose of levothyroxine, which typically causes symptoms of hyperthyroidism. C. Hypoactive deep-tendon reflexes: Hypoactive reflexes are generally a sign of hypothyroidism, not a levothyroxine overdose. In hyperthyroidism (or overdose), reflexes may be more brisk. D. Drowsiness: Drowsiness is typically seen in hypothyroidism, while levothyroxine overdose can cause symptoms of hyperthyroidism such as insomnia and increased energy.