Which lab value should the nurse monitor in a patient taking antithyroid drugs?

Choice A rationale Blood glucose levels are not a primary concern for patients taking antithyroid drugs, which are used to treat hyperthyroidism. While thyroid dysfunction can influence blood glucose, monitoring is not a routine part of antithyroid drug therapy. Blood glucose monitoring is essential for patients with diabetes mellitus, which is a separate endocrine disorder from hyperthyroidism. Choice B rationale Antithyroid drugs, such as methimazole and propylthiouracil, can cause a serious and rare adverse effect called agranulocytosis, which is a severe reduction in the number of granulocytes, a type of white blood cell. A complete blood count (CBC) is essential to monitor for this life-threatening condition by checking the white blood cell (WBC) count, particularly the neutrophil count. Normal WBC count is 4.5 to 11.0 × 10³ cells/mcL. Choice C rationale Serum calcium levels are primarily monitored in conditions related to parathyroid hormone and calcium metabolism, such as hypoparathyroidism or hyperparathyroidism. Antithyroid medications do not directly affect serum calcium levels. Monitoring serum calcium is not a routine part of the management of a patient on antithyroid drugs. Choice D rationale The lipid profile, which includes cholesterol and triglycerides, is not routinely monitored for patients on antithyroid drugs. While hyperthyroidism can affect lipid metabolism, antithyroid drugs themselves do not have a significant or primary effect on lipid levels that requires routine monitoring. Choice E rationale Serum sodium levels are not a primary concern when a patient is taking antithyroid medications. Hyponatremia or hypernatremia can be caused by various other conditions, such as dehydration, kidney disease, or certain diuretics, but it is not a direct or common side effect of antithyroid drugs. Choice F rationale Serum potassium levels are not routinely monitored for patients taking antithyroid drugs. Hyperkalemia or hypokalemia can be caused by various other conditions, such as kidney disease or diuretic use, but it is not a primary or common side effect of antithyroid drugs.