SODIUM IODIDE I 131 DIAGNOSTIC

11.1 Chemical Characteristics Sodium Iodide I 131 Capsules Diagnostic is a radiodioactive diagnostic agent containing sodium iodide I 131 and supplied for oral administration in a gelatin capsule. Each capsule contains no-carrier-added sodium iodide I 131, disodium edetate dihydrate USP as a stabilizer, sodium thiosulfate pentahydrate USP as a reducing agent, and dibasic sodium phosphate anhydrous USP. Sodium Iodide I 131 is designated chemically as Na131I and has a molecular weight of 153.99. 11.2 Physical Characteristics Iodine I 131 decays by beta emission and associated gamma emission with a physical half-life of 8.04 days. The principal radiation emissions are listed in Table 4. Table 4 Principal Radiation Emission Data from Decay of Sodium Iodide I 131 Radiation Mean % per Disintegration Mean Energy (keV) Beta-1 2.13% 69.4 Beta-3 7.20% 96.6 Beta-4 89.4% 191.6 Gamma-7 6.14% 284.3 Gamma-14 81.2% 364.5 Gamma-18 7.12% 637.0 11.3 External Radiation The specific gamma-ray constant for iodine I 131 is 4.26 x 10 -13 C•m 2 •kg -1 •MBq -1 •s -1 (2.2 R•cm 2 /mCi•hr). The first half-value thickness of lead (Pb) for iodine I 131 is 0.27 cm. A range of values for the relative attenuation of the radiation emitted by iodine I 131 that results from interposition of various thicknesses of Pb is shown in Table 5. For example, the use of 2.59 cm of Pb will decrease the external radiation exposure by a factor of about 100. Table 5 Radiation Attenuation of Iodine I 131 by Lead Shielding Shield Thickness (Pb) cm Coefficient of Attenuation 0.27 0.5 0.56 0.25 0.99 10 -1 2.59 10 -2 4.53 10 -3 To correct for physical decay of iodine I 131, the fractions that remain at selected intervals after the time of calibration are shown in Table 6. Table 6 Physical Decay Chart: Iodine I 131, Half-Life 8.04 days Days Fraction Remaining Days Fraction Remaining Days Fraction Remaining 0 Calibration Time 1.000 11 0.388 22 0.151 1 0.918 12 0.356 23 0.138 2 0.842 13 0.327 24 0.127 3 0.773 14 0.300 25 0.116 4 0.709 15 0.275 26 0.107 5 0.651 16 0.253 27 0.098 6 0.597 17 0.232 28 0.090 7 0.548 18 0.213 29 0.083 8 0.503 19 0.195 30 0.076 9 0.461 20 0.179 10 0.423 21 0.164

Sodium Iodide I 131 Capsules Diagnostic is indicated for use in adults for: Assessment of thyroid function using radioactive iodine (RAI) uptake test Imaging the thyroid (scintigraphy) Sodium Iodide I 131 Capsules Diagnostic is a radioactive diagnostic agent indicated for the assessment of thyroid function and for thyroid imaging.

Use careful handling with appropriate safety measures to minimize radiation exposure to patients and healthcare workers. ( 2.1 , 5.2 ) Follow suitable radioactivity calibration prior to administration. ( 2.1 ) In an adult patient, recommended doses are ( 2.2 ): Thyroid Function: 0.185 to 1.1 megabecquerels (MBq) [5 to 30 microcuries (microCi)] Thyroid Imaging: 1.85 to 3.70 MBq (50 to 100 microCi) 2.1 Radiation Safety Sodium Iodide I 131 Capsules Diagnostic is a radioactive drug and should be handled with appropriate safety measures to minimize radiation exposure to the patient and healthcare worker [see Warnings and Precautions ( 5.2 ) ]. Use waterproof gloves during the entire handling and administration procedure. Maintain adequate shielding during the life of the product. Open the capsule-containing vial in a well ventilated hood to avoid exposure to trace levels of volatile I-131 which may be present. Measure patient dose by a suitable radioactivity calibration system immediately prior to administration. 2.2 Recommended Dosage and Administration Instructions Administer Sodium Iodide I 131 Capsules Diagnostic orally prior to scanning. The recommended dose of Sodium Iodide I 131 Capsules Diagnostic for an adult patient is the following: Thyroid Function: 0.185 to 1.1 megabecquerels (MBq) [5 to 30 microcuries (microCi)]. Administer 24 hours before uptake measurement. Thyroid Imaging (Scintigraphy): 1.85 to 3.70 MBq (50 to 100 microCi). Administer 16 -24 hours before imaging. Consult the color-coded decay calendar that is updated in January of every year to determine which colored capsule(s) correspond to the prescribed dose: https://www.draximage.com/products/us/draximage-i-131-diagnostic-capsules/ or calculate the correct dose from the date and time of calibration provided on the container label. Prior to Sodium Iodide I 131 Capsules Diagnostic Administration Obtain a pregnacy test in females of reproductive potential prior to administration to verify the absence of pregnancy [see Contraindications ( 4 ) and Use in Specific Populations ( 8.1, 8.3 ) ]. Advise patients to maintain a low-iodine diet two weeks prior to radioiodine administration and continue for several days during the uptake or imaging process [see Drug Interactions ( 7 ) ]. Advise patients to fast at least 2 hours before and 2 hours after administration to ensure absorption. Advise patients to hydrate before and after administration of radioiodine and void frequently to ensure rapid excretion. 2.3 Radiation Dosimetry The biokinetic and radiation dose distributions associated with thyroid uptake of iodide I 131 depend on dietary intake of stable iodine. A range of uptake percentages in an average adult (73.7 kg) are shown in Table 1. For a thyroid blocked from iodide uptake in the production of hormones, the effective half-life of iodide I 131 is approximately 1.4 hours; for "low" to "high" uptake, the effective half-life of I 131 ranges from approximately 80 to 90 hours. Table 1 Absorbed dose per unit activity sodium iodide I 131 administered orally (mGy/MBq) in adult (73.7-kg reference model) Organ Thyroid uptake of I 131 (% administered activity A 0 ) 24 h after oral administration Blocked thyroid (0% A 0 ) Low uptake (16% A 0 ) Medium uptake (26% A 0 ) High uptake (36% A 0 ) Adrenals 0.044 0.051 0.055 0.059 Bone surfaces 0.030 0.089 0.12 0.16 Brain 0.021 0.093 0.13 0.17 Breast 0.020 0.038 0.048 0.058 Gallbladder wall 0.037 0.043 0.046 0.049 Gastrointestinal tract Stomach wall 0.87 0.77 0.71 0.66 Small intestine wall 0.035 0.033 0.032 0.032 Colon wall 0.14 0.14 0.14 0.14 (Upper large intestine wall) 0.12 0.12 0.12 0.12 (Lower large intestine wall) 0.17 0.17 0.17 0.16 Heart wall 0.062 0.089 0.10 0.12 Kidneys 0.27 0.27 0.27 0.27 Liver 0.050 0.093 0.12 0.14 Lungs 0.053 0.10 0.13 0.15 Muscles 0.026 0.084 0.12 0.15 Oesophagus 0.024 0.10 0.14 0.19 Ovaries 0.038 0.037 0.036 0.035 Pancreas 0.060 0.064 0.066 0.068 Red marrow 0.031 0.072 0.095 0.12 Salivary glands 0.27 0.22 0.19 0.16 Skin 0.019 0.043 0.057 0.071 Spleen 0.064 0.069 0.072 0.075 Testes 0.025 0.024 0.023 0.22 Thymus 0.024 0.10 0.14 0.19 Thyroid 2.2 280 430 580 Urinary bladder wall 0.54 0.45 0.39 0.34 Uterus 0.045 0.042 0.040 0.038 Remaining organs 0.029 0.84 0.11 0.15 Effective dose per administered activity (mSv/MBq) 0.28 14 22 29

Sodium Iodide I 131 Capsules Diagnostic is contraindicated in pregnancy [see Warnings and Precautions ( 5.1 ) , Use in Specific Populations ( 8.1 ) ]. Pregnancy

The following adverse reaction has been described elsewhere in the labeling: Hypersensitivity Reactions [see Warnings and Precautions ( 5.4 ) ] The following adverse reactions have been identified during post-approval use from Sodium Iodide I 131 Capsules Diagnostic. Because these reactions are voluntarily reported from a population of uncertain size, it is not always possible to reliably estimate their frequency or establish a causal relationship to drug exposure. Adverse reactions associated with the administration of Sodium Iodide I 131 Capsules Diagnostic are: Gastrointestinal disorders: vomiting, nausea, and diarrhea General disorders and administration site conditions: local thyroid swelling Immune system disorders: hypersensitivity reactions Skin and subcutaneous tissue disorders: itching, rash, hives, and erythema Common adverse reactions reported with diagnostic doses of sodium iodide I 131 include nausea, vomiting, itching, rash and hives. ( 6 ) To report SUSPECTED ADVERSE REACTIONS, contact Jubilant DraxImage Inc. at 1-888-633-5343 or FDA at 1-800-FDA-1088 or www.fda.gov/medwatch.

Certain drugs and iodine-containing foods interfere with the accumulation of radioiodide by the thyroid. Review the patients history, current medications, and recent diagnostic tests prior to the administration of Sodium Iodide I-131 Capsules Diagnostic. Advise patients to maintain a low-iodine diet two weeks prior to radioiodine administration and continue for several days during the uptake or imaging process and to discontinue the following products before they undergo the procedure as shown in Table 3: Table 3 Pharmaceuticals/OTCs/Agents Blocking Radioiodine Uptake ​Products Recommended duration of withdrawal Thionamide medications (e.g., propylthiouracil, methimazole carbimazole) 3 days Multivitamins containing iodide 10 days Natural or synthetic thyroid hormones triiodothyronine thyroxine 2 weeks 4 weeks Iodine containing foods: iodinized salt, dairy products, egg yolks, seafood, turkey, and liver 2 weeks Kelp, agar, carrageenan, Lugol solution 3 weeks Saturated solution of potassium iodide 3 weeks Topical iodine (e.g., surgical skin preparation) 3 weeks Radiographic contrast agents Water soluble Lipophilic 2 months 6 months Amiodarone 6 months The recent intake of iodine in any form or the use of thyroid or anti-thyroid drugs will affect the uptake of sodium iodide I 131. ( 5.3 , 7 )