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 are associated with hypothyroidism, not levothyroxine overdose. B. Constipation is a symptom of hypothyroidism and would suggest under-treatment, not overdose. C. Insomnia is a sign of hyperthyroidism, which can occur with levothyroxine overdose due to increased metabolic activity. Other signs may include tachycardia, anxiety, weight loss, and heat intolerance. D. Drowsiness is more consistent with hypothyroidism and is not expected with overdose.