July 27, 2016
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Hicon Side Effects Center

Medical Editor: John P. Cunha, DO, FACOEP

Last reviewed on RxList 6/8/2016

Hicon (Kit for the Preparation of Sodium Iodide I 131 Capsules and Solution Therapeutic - Oral) is radioactive Sodium Iodide indicated for the treatment of hyperthyroidism and selected cases of thyroid cancer. Generic radioactive Sodium Iodide may be available to some medical specialists. Side effects of Hicon include:

  • hypersensitivity reactions
  • radiation toxicities, and
  • metabolic events

Immediate adverse reactions typically are related to:

  • hypersensitivity
  • severe allergic reaction (anaphylaxis)
  • rash
  • hives
  • bronchospasm, and
  • other allergic events.

Severe side effects of Hicon may include radiation thyroiditis and renal function impairment.

Hicon comes in the strength of 37 gigabecquerels/mL or GBg (1,000 millicuries/mL). Each mL of the concentrated solution contains 37 GBq of no-carrier-added Sodium Iodide. Hicon comes in three strengths; 250, 500 and 1000 millicuries/ml. The concentrated Sodium Iodide I 131 Solution USP provided with Hicon must not be used for direct administration to patients. It must be diluted and prepared. The recommended dosage for orally administered Sodium Iodide I 131 Solution USP is based on the thyroid gland uptake as well as the size of the gland. Thyroidal uptake and size should be determined by the physician prior to treatment and may be useful in calculating the therapeutic dose to be administered to the individual patient. Hicon is radioactive and only should be administered by qualified nuclear physicians and/or radiopharmacists. Hicon may interact with other drugs. Tell your doctor all medications and supplements you use. Sodium Iodide I-131 may cause harm to the fetus's thyroid gland when administered to a pregnant woman. Radioiodide crosses the placenta and may cause severe and irreversible hypothyroidism in newborns. Women of childbearing age must use the appropriate contraceptive measures. Sodium Iodide I 131 is found in the breast milk of nursing mothers. Formula feeding should be substituted for breast feeding until radiation levels have substantially decreased. Safety and efficacy in pediatric patients have not been established; Hicon is not usually used in people younger than 30 years old.

Our Hicon Side Effects Drug Center provides a comprehensive view of available drug information on the potential side effects when taking this medication.

This is not a complete list of side effects and others may occur. Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088.

What is Prescribing information?

The FDA package insert formatted in easy-to-find categories for health professionals and clinicians.

Hicon FDA Prescribing Information: Side Effects
(Adverse Reactions)


Adverse events associated with the class of Sodium Iodide I-131 drug product include hypersensitivity reactions, radiation toxicities, and metabolic events.

Immediate adverse reactions typically are related to hypersensitivity; e.g., anaphylaxis, rash, hives, bronchospasm, and other allergic events.

Radiation adverse events are related to the dose include the following:

Bone marrow depression, leukopenia, thrombocytopenia, acute leukemia, anemia, blood dyscrasia, chromosomal abnormalities, radiation sickness, and death. Delayed radiation toxicity includes radiation thyroiditis, gastritis and sialadentis.

Metabolic adverse events include hypothyroidism and exaggerated hyperthyroidism due to radiation thyroiditis.

Tenderness and swelling of the neck, pain on swallowing, sore throat and cough may occur about the 3rd day after treatment.

Drug Abuse And Dependence

Patients administered Sodium Iodide I 131 Solution USP are not at risk for developing chemical dependency.

Read the entire FDA prescribing information for Hicon (Sodium Iodide I 131)

Report Problems to the Food and Drug Administration


You are encouraged to report negative side effects of prescription drugs to the FDA. Visit the FDA MedWatch website or call 1-800-FDA-1088.

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