Side effects of radioactive iodine

Many people will not have any side effects following radioactive iodine. Side effects that you may have include:

  • a sore neck and throat
  • a dry mouth
  • taste changes
  • nausea (feeling sick).

Let your doctor or nurse know if you have any of these symptoms as they can prescribe medicines to help.

A rare, long-term side effect of radioactive iodine treatment is a dry mouth. This can happen if the radioactive iodine is absorbed by the salivary glands. Let your doctor know if you develop a dry mouth.

Pregnancy, breastfeeding and fertility

If you stopped breastfeeding before your radioactive iodine, it isn’t safe to start breastfeeding again after your treatment. However, it will be safe for you to do so after future pregnancies.

You should not become pregnant or father a child while being treated for thyroid cancer. You should not become pregnant for at least six months or father a child for at least four months after radioactive iodine. It is important to use contraception during this time.

Fertility isn’t normally affected by radioactive iodine treatment. However, there is a very small risk for men who need to have repeated treatments. In this case, you may be offered sperm banking. Your doctor or nurse can give you more information and support about this.

Back to Radioactive iodine

What is radioactive iodine?

Radioactive iodine is a type of radioisotope often used to treat thyroid cancer. It is given as a drink or capsule.