A nurse is assessing a client who has Graves' disease and is taking methimazole. Which of the following findings indicates the client needs a lower dose of the medication?

The correct answer is C: Bradycardia. Methimazole is used to treat hyperthyroidism in patients with Graves' disease. One of the side effects of methimazole is bradycardia, which is a slower than normal heart rate. If the client is experiencing bradycardia, it indicates that the dose of methimazole may be too high and needs to be decreased to prevent further complications. Exophthalmos, diaphoresis, and weight loss are common symptoms of hyperthyroidism and would not necessarily indicate a need for a lower dose of methimazole.