A patient with hyperthyroidism is scheduled for radioactive iodine therapy.
Which instruction will be included by the nurse to the patient?

Choice A rationale

Alpha blockers primarily exert their effects on the vascular smooth muscle by blocking alpha-1 adrenergic receptors. This action leads to vasodilation, which lowers blood pressure. They do not have a direct mechanism of action that would precipitate acute renal failure upon first dose administration. Renal function, while monitored, is not the most immediate or common adverse effect to assess for.

Choice B rationale

Alpha-1 adrenergic receptors, when blocked by alpha blockers, cause vasodilation of both arteries and veins. This leads to a decrease in peripheral vascular resistance and venous return, causing a significant drop in blood pressure. This effect, known as orthostatic hypotension or "first-dose phenomenon," is a common and critical adverse effect to assess for, as it can cause dizziness and fainting.

Choice C rationale

Blood dyscrasias, or disorders involving the cellular components of blood, are not a typical or immediate adverse effect associated with the first administration of an alpha blocker. While some medications can cause these rare side effects over long-term use, the acute and most common concern with the initial dose is related to its cardiovascular effects on blood pressure.

Choice D rationale

While alpha blockers can indirectly affect the heart rate through baroreceptor reflexes in response to hypotension, they are not typically associated with the direct induction of significant dysrhythmias as a primary adverse effect upon first administration. The immediate and most profound hemodynamic effect is the peripheral vasodilation and subsequent hypotension, which takes precedence in initial assessment.

Choice A rationale

Radioactive iodine (RAI) therapy involves the patient ingesting a capsule containing iodine-131, which targets and destroys overactive thyroid cells. The patient's bodily fluids, including saliva, sweat, and urine, become temporarily radioactive. To protect others, especially pregnant women and young children who are more susceptible to radiation, close contact must be avoided for several days to a week.

Choice B rationale

Continuing thyroid medication is incorrect. Antithyroid medications like propylthiouracil or methimazole, used to manage hyperthyroidism, must be stopped several days before radioactive iodine therapy. These drugs can interfere with the uptake of the radioactive iodine by the thyroid gland, reducing the effectiveness of the treatment. This is a crucial instruction for treatment success.

Choice C rationale

A high-iodine diet is incorrect. The patient is instructed to follow a low-iodine diet for one to two weeks before the procedure. A low-iodine diet depletes the body's iodine stores, making the thyroid gland "hungry" for iodine. This enhanced uptake ensures that the radioactive iodine is more effectively absorbed by the thyroid cells, increasing treatment efficacy.

Choice D rationale

Increased fluid intake is a correct instruction. Consuming a generous amount of fluids after the procedure helps to flush any unabsorbed radioactive iodine out of the body through the urinary system. This helps to reduce the radiation exposure to other organs and tissues, particularly the salivary glands and the bladder, and minimizes side effects.

Choice E rationale

A low-iodine diet is a correct instruction. As noted in the rationale for choice C, a low-iodine diet is essential for maximizing the uptake of the radioactive iodine by the thyroid gland. By decreasing the body's circulating iodine levels, the thyroid gland becomes more receptive to the radioactive iodine, thereby enhancing the therapeutic effect of the treatment.

Choice F rationale

Prolonged intimate contact should be avoided. Due to the temporary radioactivity of body fluids and sweat, close contact, including kissing and sexual intercourse, should be avoided for several days to a week. The patient must also avoid sharing utensils and using separate bathrooms to prevent transferring radioactive material to others, particularly vulnerable individuals.