A nurse is reviewing the medical record of a client who has been on levothyroxine for several months. Which of the following findings indicates a therapeutic response to the medication?

A. A decrease in T4 would indicate worsening hypothyroidism, not a therapeutic response. B. An increase in sleep may occur with untreated hypothyroidism; effective treatment usually restores normal energy levels, reducing excessive sleepiness. C. Levothyroxine replaces thyroid hormone, which leads to a decrease in TSH levels through negative feedback—this is a key indicator of a therapeutic response. D. An increase in weight is a symptom of untreated or under-treated hypothyroidism. A therapeutic response would more likely include weight stabilization or loss.