Which outcome indicates that a client is experiencing over-treatment with methimazole?

The outcome indicating that a client is experiencing over-treatment with methimazole is characterized by fatigue and bradycardia. Methimazole is an antithyroid medication used to manage conditions such as hyperthyroidism by inhibiting the synthesis of thyroid hormones. Over-treatment with this medication can lead to excessive suppression of thyroid hormone production, resulting in symptoms of hypothyroidism.

Fatigue is a common symptom associated with reduced metabolic rates, which occurs when thyroid hormone levels are insufficient. Additionally, bradycardia, or a slowed heart rate, often accompanies fatigue as a result of decreased sympathetic nervous system activity associated with low thyroid hormone levels. Both of these symptoms indicate that the body's metabolism is slowing down due to inadequate levels of circulating thyroid hormones.

In contrast, the other listed symptoms do not align with the effects of over-treatment. Increased appetite and weight gain typically occur when a person is hyperthyroid or when treatment is insufficient. Insomnia and heightened anxiety relate to stimulation of the nervous system, commonly associated with hyperthyroidism rather than over-treatment. Warm and moist skin suggests hyperactivity of the thyroid, which again is not consistent with the effects of too much methimazole leading to thyroid underactivity.