May 29, 2017
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Sodium Iodide I 131

"The U.S. Food and Drug Administration today granted approval to Lenvima (lenvatinib) to treat patients with progressive, differentiated thyroid cancer (DTC) whose disease progressed despite receiving radioactive iodine therapy (radioactive iodine"...


Sodium Iodide I 131

How Supplied


Sodium Iodide I 131 (sodium iodide i 131 (sodium iodide i 131 capsules) capsules) is indicated for use in performance of the radioactive iodide (RAI) uptake test to evaluate thyroid function. Diagnostic doses may also be employed in localizing metastases associated with thyroid malignancies.


The suggested oral dosage ranges employed in the average patient (70 kg) for diagnostic procedures for thyroid function are as follows:

Thyroid Uptake: 0.185 to 0.555 megabecquerels (5 to 15 microcuries)

Scintiscanning:1.85 to 3.7 megabecquerels (50 to 100 microcuries)

Localization of extra-thyroidal metastases: 37 megabecquerels (1000 microcuries).

Waterproof gloves should be used during the entire handling and administration procedure.

The patient dose should be measured by a suitable radioactivity calibration system immediately prior to administration.

Radiation Dosimetry

The estimated absorbed radiation doses2 to an average (70 kg) euthyroid (normal functioning thyroid) patient from an oral dose of 3.7 megabecquerels (100 microcuries) of iodine I-131 are shown in Table 4.

Table 4. Absorbed Radiation Doses

Tissue Absorbed radiation doses for 3.7 megabecquerels (100 Microcuries)
Thyroid Uptake
5% 15% 25%
mGy rads mGy rads mGy rads
Thyroid 260 26.0 800 80.0 1300 130.0
Stomach Wall 1.7 0.17 1.6 0.16 1.4 0.14
Red Marrow 0.14 0.014 .20 0.020 0.26 0.026
Liver 0.20 0.020 0.35 0.035 0.48 0.048
Testes 0.08 0.008 0.09 0.009 0.09 0.009
Ovaries 0.14 0.014 0.14 0.014 0.14 0.014
Total Body 0.24 0.024 0.47 0.047 0.71 0.071

2MIRD DOSE ESTIMATE REPORT No. 5. Summary of Current Radiation Dose Estimates to Humans from 123I, 124I, 125I, 126I, 130I, 131I, and 132I Sodium Iodide. J. Nucl. Med., 16, No. 9, 857-60 (1975).


Catalog Number 300.

Sodium Iodide I 131 (sodium iodide i 131 (sodium iodide i 131 capsules) capsules) Diagnostic Capsules are supplied in a strength of 3.7 megabecquerels (100 microcuries) at time of calibration.

The capsules are packaged in plastic vials containing 5, 10, or 15 capsules per vial.

Storage And Handling

Sodium Iodide I 131 (sodium iodide i 131 (sodium iodide i 131 capsules) capsules) Diagnostic capsules should be stored at controlled room temperature 20-25°C (68-77°F) [See USP].

Storage and disposal of Sodium Iodide I 131 (sodium iodide i 131 (sodium iodide i 131 capsules) capsules) Diagnostic Capsules should be controlled in a manner that is in compliance with the appropriate regulations of the government agency authorized to license the use of this radionuclide.

The U.S. Nuclear Regulatory Commission has approved distribution of this radiopharmaceutical to persons licensed to use byproduct material listed in Section 35.100, and to persons who hold an equivalent license by an Agreement State.

Revised 1/2003. Mallinckrodt Inc., St. Louis, MO 63134.

This monograph has been modified to include the generic and brand name in many instances.

Last reviewed on RxList: 5/19/2009

How Supplied

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