What is in this leaflet
This leaflet answers some common questions about Sodium Iodide (131I) therapy capsules. It does not contain all the available information. It does not take the place of you talking to your nuclear medicine physician or specialist. All treatments have potential risks and benefits associated with them.
Your nuclear medicine physician or specialist has weighed the small risk of your being treated with a Sodium Iodide (131I) therapy capsule against the benefits it is expected you will receive from it.
If you have any concerns about being given this capsule, discuss them with your nuclear medicine specialist.
Keep this leaflet.
You may need to read it again.
What a Sodium Iodide (131I) therapy capsule is used for
Sodium Iodide (131I) is used to treat disorders of the thyroid gland. This gland controls the body’s physical and chemical processes by producing hormones triiodothyronine (T3) and thyroxine (T4).
Sodium Iodine (131I) is a radioisotope which emits high energy electrons (beta particles). When administered orally the Iodine - 131 from the capsules is taken up by the thyroid gland tissue. Beta radiations from the Iodine - 131 help reduce the activity of the tissue in proportion to the amount absorbed.
Ask your nuclear medicine physician or specialist if you have any questions about why a Sodium Iodide (131I) therapy capsule is being given to you or why you have been referred for this treatment.
For more information ask for a copy of the booklet “Nuclear Medicine - Answering your Questions” available from the hospital, clinic or supplier.
Before you are given this medicine
It is extremely Important to tell your nuclear medicine physician or specialist if:
- You are pregnant or intend to become pregnant
It is known that the Sodium Iodide (131I) contained in this capsule may be harmful to an unborn baby when administered to a pregnant woman.
Sodium Iodide (131I) will only be given in pregnancy after weighing the needs of the mother against any risk to the foetus.
If you intend to become pregnant consult your doctor about the advised waiting period. - You are breast-feeding
It is normal practice to stop breast-feeding and substitute formula feeding from the time you are given the capsule. It is known that Sodium Iodide (131I) passes into breast milk. - You have eaten seafood, or foods with high iodine content lately
Discuss your diet over the previous three days as iodine consumed in food may have an effect on your treatment.
If you have not told your nuclear medicine physician or specialist about any of the above, tell them before you are given a Sodium Iodide (131I) therapy capsule.
Taking other medicine
Tell your nuclear medicine physician or specialist if you are taking any other medicines including medicines that you buy without a prescription from your pharmacy, supermarket or health food store.
Your medication’s constituents may affect the results of this treatment. Your nuclear medicine physician or specialist will advise you of what to do.
How Sodium Iodide (131I) therapy capsules are used
How it is given
Sodium Iodide (131I) therapy capsules can only be administered by qualified staff with specific training in the safe use and handling of radiopharmaceuticals.
A Sodium Iodide (131I) therapy capsule is given with a drink. It must be swallowed whole - do not chew the capsule. You may be asked to take food and drink to aid digestion of the capsule.
If you have any questions as to why you have been prescribed a Sodium Iodide (131I) Therapy Capsule, ask your nuclear medicine specialist or doctor.
Test procedure
After taking your capsule you may be asked to stay in hospital for a period (spanning from few hours to few days) to monitor the treatment.
After your treatment you may be asked to have another scan, similar to your original diagnostic scan, at a later date.
After you go home
Continue your day-to-day activities. However, it is IMPORTANT to observe the following for one week after the treatment as the Iodine-131 (131I) leaves your body:
- avoid being closer than 1 metre to other persons for an extended duration.
- drink plenty of fluids.
- avoid close physical contact with children and pregnant women.
- sleep in a single bed.
- shower daily and frequently wash of excess perspiration.
Side effects
Tell your nuclear medicine specialist or technologist as soon as possible if you do not feel well after taking your Sodium Iodine (131I) therapy capsule.
Rare minor reactions such as nausea, vomiting, increased heartbeat, itching and rash have been reported with the use of Sodium Iodide (131I) therapy capsules. It is unlikely that these effects are caused by very small amounts of Iodine-131 in the capsule.
When larger doses of Iodine-131 are used, reported sided effects include radiation thyroiditis, sialitis and transient worsening of hyperthyroidism.
Potential effects of a high dose of Iodine-131 include nausea, pulmonary fibrosis, bone marrow depression, leukaemia and acute thyroid crisis.
NOTE: Adequate long term studies have not been performed in animals to determine whether this drug affects fertility, or has teratogenic or mutagenic potential. Safety and efficacy in children have not been established.
Storage and Expiry
Sodium Iodide (131I) therapy capsules are stored by the hospital or clinic. The capsules are stored in a dry place below 25°C.
Your nuclear medicine physician or technologist will check the expiry date before giving you a Sodium Iodide (131I) therapy capsule.
Product description
What is looks like
A Sodium Iodide (131I) therapy capsule is a pale yellow gelatine capsule. It comes in a 10 mL vial.
Ingredients
Active ingredient:
- Sodium Iodide (131I)
Inactive ingredients:
- Sodium phosphate - dibasic (anhydrous)
- Sodium bicarbonate
- Water for Injection
- Gelatine (animal origin) capsule shells with the following food grade colours:
- Iron Oxide Yellow (CI77492)
- Titanium Oxide (CI77891)
- Erythrosine Red No.3 (CI45430)
- Carbon Black (CI77266)
Aust R 22808
Supplier
ANSTO Health
Locked Bag 2001
Kirrawee DC, NSW 2232
Telephone: 1800 251 572
Facsimile: 02 9543 6511

ANSTO Health is a commercial enterprise of the Australian Nuclear Science and Technology Organisation (ANSTO), which is located at Lucas Heights in Sydney. NSW.
Date Revised: January 2012
Date of Printing: January 2012