Skip to main content

i3odine Max Dosage

Generic name: SODIUM IODIDE I-131 3500mCi in 1mL
Dosage form: kit, capsules and solution
Drug classes: Antithyroid agents, Therapeutic radiopharmaceuticals

Medically reviewed by Last updated on Jun 9, 2022.

Radiation Safety

  • I3odine MAXTM is a radioactive drug. Handle with appropriate safety measures to minimize radiation exposure to the patient and healthcare workers [see Warnings and Precautions (5.7)]:
    • Use only by, or under the direction of, physicians who are qualified by specific training and experience in the safe use and handling of radioactive materials, and whose experience and training have been approved by the appropriate governmental agency authorized to license the use of radiopharmaceuticals.
    • Use waterproof gloves when handling and administering the product.
    • Maintain adequate shielding during the life of the product.
    • Measure patient dose with a suitable radioactivity calibration system immediately prior to administration.

Important Administration Instructions

  • Do not directly administer the concentrated sodium iodide I 131 solution provided with I3odine MAXTMto patients. The concentrated sodium iodide I 131 solution must be diluted and prepared prior to administration [see Dosage and Administration (2.4)].
  • Obtain a pregnancy test in females of reproductive potential prior to administration to verify the absence of pregnancy [see Contraindications (4) andUse in Specific Populations (8.1,8.3)].
  • Instruct patients to fast at least 2 hours before and 2 hours after administration to ensure absorption.
  • Instruct patients to hydrate before and after administration of sodium iodide I 131 and to void frequently to enhance urinary elimination of the radioiodide that is not absorbed by the thyroid gland [see Warnings and Precautions (5.2)].
  • Instruct patients to maintain a low-iodide diet two weeks prior to radioiodide administration and continue for several days during the uptake or imaging process [see Warnings and Precautions (5.8) and Drug Interactions (7)].
  • Instruct patients to discontinue the anti-thyroid therapy three days before administration of sodium iodide I 131 [see Warnings and Precautions (5.8) and Drug Interactions (7)].
  • For patients with a history of renal impairment, evaluate renal function for therapeutic planning and consider dosimetry [see Use in Specific Populations (8.6)].
  • Obtain a complete blood count within one month of therapy. If patients show leukopenia or thrombocytopenia, dosimetry should be used to determine a safe sodium iodide I 131 activity, while delivering less than 2 Gy to the bone marrow [see Warnings and Precautions (5.2)].

Recommended Dosage and Administration

Individualization of Therapy
The recommended dose for orally administered sodium iodide I 131 capsules or solution 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.

Treatment of Hyperthyroidism
The recommended dose is 148 to 370 MBq (4 to 10 mCi) administered orally. Toxic nodular goiter may require a larger dose.

Treatment of Thyroid Carcinoma
The recommended dose is 1100 to 3700 MBq (30 to 100 mCi) administered orally. For subsequent ablation of metastases, the recommended dose is 3700 to 7400 MBq (100 to 200 mCi) administered orally.

Dilution and Preparation Instructions

Preparation of Dilute Sodium Iodide I 131 Solution

  1. Using the calibration date and radionuclidic concentration on the label of the product vial, calculate the required volume to produce the necessary dose in MBq or mCi.
  2. Using a shielded syringe, remove the required volume.
  3. Using the shielded syringe, transfer the required volume to a suitably shielded receiving vial.
  4. Add diluent solution to the receiving vial to produce a final dose of the desired volume.
  5. The recommended diluent is Purified Water containing 0.2 % sodium thiosulfate as a reducing agent. Acidic diluents should not be used as they may cause the pH to drop below 7.5 and stimulate the volatilization of Iodine I-131 hydriodic acid.
  6. Present the dose in a shielded container for administration to the patient with a straw

Preparation of Sodium Iodide I 131 Capsules

  1. I3odine MAXTM includes one large gelatin capsule and one small gelatin capsule for each capsule dose prepared. Each large capsule is empty and each small capsule contains approximately 300 mg of dibasic sodium phosphate anhydrous as the absorbing buffer.
  2. Using the calibration date and radionuclidic concentration on the label of the product vial, calculate the required volume to produce the necessary dose in MBq or mCi.
  3. Open one large capsule supplied with I3odine MAXTM by pulling apart the capsule into two pieces as illustrated below:
    image description
  4. Insert an unopened small capsule supplied with I3odine MAXTM into the bottom half of the empty largecapsule as illustrated below:
    image description
  5. With an appropriate syringe, withdraw the required volume of sodium iodide I 131 Solution (maximum 150 microliters) from the vial as illustrated below:
    image description
  6. Inject into the center of the small capsule through the top as illustrated below:
    image description
  7. Slip the upper half of the large capsule over the bottom half to completely cover the small capsule and push down gently until locked as illustrated below:
    image description
  8. Measure the patient dose in a suitable radioactivity calibration system immediately prior to administration.
  9. Prepared capsules may be stored in a suitable polypropylene container and place inside a lead pot until use, within seven days.

Radiation Dosimetry

  • The biokinetic modeling and radiation dose distributions associated with thyroid uptake of iodide I 131 depend on dietary intake of stable iodide and presume normal production of thyroid hormone. Table 1 shows a range of uptake percentages in an average adult (73.7 kg reference model). Table 1 is not intended to be used for treatment planning.
  • 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*
Table 1 is not intended for treatment planning.
These columns are not applicable to estimate organ or effective doses in patients following thyroidectomy. In patients with thyroid cancer following thyroidectomy, organ and effective doses can be estimated from the "blocked"-thyroid-uptake values.
These values presume unimpeded production of thyroid hormone and may not be applicable to estimate thyroid dose and effective dose in patients who have had previous treatment with I 131 for hyperthyroidism
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 A0)
24 h after oral administration

Blocked thyroid
(0% A0)

Low uptake
(16% A0)

Medium uptake
(26% A0)

High uptake
(36% A0)

Adrenals 0.044 0.051 0.055 0.059
Bone surfaces


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
Esophagus 0.024 0.10 0.14 0.19
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
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 0.084 0.11 0.15
Effective dose per administered activity (mSv/MBq) 0.28 14 22 29

More about i3odine Max (sodium iodide-i-131)

Patient resources

Other brands


Professional resources

Related treatment guides

Further information

Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.