A nurse is teaching a client who is to begin taking tamoxifen to treat breast cancer. The nurse should instruct the client to expect which of the following findings as an adverse effect of the medication?

Choice A reason: Hyperkalemia is not the correct answer. Hyperkalemia is a high level of potassium in the blood. Corticosteroids do not cause hyperkalemia, but rather hypokalemia. Hyperkalemia may be caused by other factors such as renal failure, acidosis, or potassium-sparing diuretics.

Choice B reason: Hypokalemia is the correct answer. Hypokalemia is a low level of potassium in the blood. Corticosteroids can cause hypokalemia by increasing the excretion of potassium and sodium in the urine. Hypokalemia can cause muscle weakness, cramps, arrhythmias, and digoxin toxicity.

Choice C reason: Hypermagnesemia is not the correct answer. Hypermagnesemia is a high level of magnesium in the blood. Corticosteroids do not affect magnesium levels. Hypermagnesemia may be caused by other factors such as renal failure, excessive antacid use, or magnesium-containing laxatives.

Choice D reason: Hypomagnesemia is not the correct answer. Hypomagnesemia is a low level of magnesium in the blood. Corticosteroids do not affect magnesium levels. Hypomagnesemia may be caused by other factors such as malnutrition, alcoholism, or diuretic use.

Choice A reason: This is incorrect because insulin can be given intravenously in certain situations, such as diabetic ketoacidosis, hyperglycemic hyperosmolar state, or perioperative care.

Choice B reason: This is correct because regular insulin is the only type of insulin that can be administered intravenously, as it is a short-acting insulin that has a rapid onset and peak. Other types of insulin, such as intermediate-acting or long-acting, are not suitable for intravenous use, as they have a delayed onset and peak and may cause hypoglycemia.

Choice C reason: This is incorrect because insulin aspart and insulin lispro are rapid-acting insulins that have a faster onset and peak than regular insulin. They are not recommended for intravenous use, as they may cause severe hypoglycemia. They are usually given subcutaneously before meals to control postprandial blood glucose levels.

Choice D reason: This is incorrect because not all forms of insulin can be administered intravenously, as explained above. Only regular insulin can be given intravenously, and the dose may differ from the subcutaneous dose depending on the patient's blood glucose level and insulin sensitivity.