Are there any side effects to antithyroid drugs?
In about 5% of cases, antithyroid drugs cause allergic reactions such as skin rashes, hives, and sometimes fever and joint pains. A much more serious potential side effect is a decrease in the white blood cells that are a part of the immune system, thereby causing a decrease in your resistance to infection. In very rare cases, these cells may disappear entirely (a condition called agranulocytosis), which can be potentially fatal if there is a serious infection.
If, while taking these drugs, you experience an infection, stop taking the drug immediately and get a white blood count that same day. If the white count has been lowered and you continue taking the drug, the infection could become fatal. However, a lowered white count will return to normal once you have stopped taking the drug. Hypothyroidism can result from the use of antithyroid drugs, although it is far less likely to result from this treatment than from surgery or radiation.
If the drugs don't work, what is the next treatment option?
Most hyperthyroid patients wind up being treated with radioactive iodine (I-131), otherwise known as RAI. RAI is administered by mouth, by means of a capsule or a liquid. The RAI goes from the stomach into the bloodstream and eventually into the thyroid gland. The RAI lodges there because the thyroid gland needs iodine to produce the thyroid hormone, and therefore the thyroid gland will readily takes up the iodine from the bloodstream. In the thyroid gland, the radiation destroys some of the thyroid cells, thereby reducing production of the thyroid hormone.
What happens to this radiation in my body?
Eventually, the body will pass much of the RAI out through urine. The RAI can also be excreted in the saliva, perspiration, and stools. Any remaining RAI will become nonradioactive.
Then just how safe is this radiation treatment?
This treatment has been used since 1940, and no serious complications from RAI treatment have become apparent over nearly 50 years of use. However, RAI should not be taken during pregnancy or breast feeding.
How fast does RAI work?
Most patients get relief in three to six months. However, if the initial dose was too small, it may need to be repeated.
Are there any side effects to Radioactive Iodine use?
The main side effect is that most patients develop hypothyroidism, or an underactive thyroid gland, after RAI. This condition is then treated with a thyroid hormone supplement. This may seem silly--trading one thyroid problem for another--but hyperthyroidism is much more dangerous and difficult to control than is hypothyroidism. So, while becoming hypothyroid may not be a perfect outcome, it is much better than being hyperthyroid.
Are there any alternatives to the drugs or radiation?
Surgery to remove all or part of the thyroid gland (known as a thyroidectomy) will permanently cure hyperthyroidism. However, several things need to happen before surgery takes place.
First, surgery can be risky unless the hyperthyroidism is already being controlled by an antithyroid or a beta blocking drug. Therefore, you will take either propylthiouracil or Tapazole to lower your thyroid hormone levels. You should reach normal levels in about six weeks
Often, for several days prior to surgery, you will also take some drops of nonradioactive iodine (either Lugol's iodine or supersaturated potassium iodide). This has the effect of reducing the blood supply to the thyroid gland, thereby making surgery easier and safer.
The goal of the surgery is to remove just enough of the gland so that thyroid production is back to normal. If too much is taken, than the patient can become hypothyroid.
There can also be other complications resulting from the surgery. One is vocal cord paralysis. Another is accidental removal of the parathyroid glands, which are located in the neck in back of the thyroid gland. Because the parathyroid glands regulate the amount of calcium in the body, their removal will result in low calcium levels.
Surgery is now reserved for special cases, including:
pregnant women who cannot tolerate antithyroid medication, and
people who do not want RAI but do want a permanent form of treatment