Sodium Iodide I-123

FDA Drug Information • Also known as: Sodium Iodide I 123

Brand Names: Sodium Iodide I 123
Dosage Form: SOLUTION
Product Type: BULK INGREDIENT

Description

DESCRIPTION Sodium Iodide I 123 (Na 123 I) for diagnostic use is supplied in capsules for oral administration. The capsules are available in strengths of 3.7 and 7.4 megabecquerels (MBq) (100 and 200 μCi) I 123 at time of calibration. Each capsule contains 0.3 µg - 3 µg Sodium Thiosulfate as a stabilizer. The radionuclidic composition at calibration is not less than 97.0 percent I 123, not more than 2.9 percent I 125 and not more than 0.1 percent all others (I 121 or Te 121.) The radionuclidic composition at expiration time is not less than 87.2 percent I 123, not more than 12.4 percent I 125 and not more than 0.4 percent all others. The ratio of the concentration of I 123 and I 125 changes with time. Graph 1 shows the maximum concentration of each as a function of time. Graph 1 Radionuclidic Concentration of I 123 and I 125 Physical Characteristics Sodium Iodide I 123 decays by electron capture with a physical half-life of 13.2 hours. The photon that is useful for detection and imaging studies is listed in Table 1 . Table 1 Principal Radiation Emission Data 1 1 Kocher, David C., Radioactive Decay Data Tables, DOE/TIC-11026, 122, (1981) Radiation Mean %/Disintegration Mean Energy (keV) Gamma-2 83.4 159 External Radiation The specific gamma ray constant for I 123 is 1.6 R/hr-mCi at 1 cm. The first half value thickness of lead (Pb) for I 123 is 0.005 cm. A range of values for the relative attenuation of the radiation emitted by this radionuclide that results from the interposition of various thicknesses of Pb is shown in Table 2 . For example, the use of 1.63 cm of lead will decrease the external radiation exposure by a factor of about 1,000. Table 2 Radiation Attenuation by Lead Shielding 2 2 Shleien, Bernard, The Health Physics and Radiological Health Handbook, Table 6.1.2, 169, (1992) Shield Thickness (Pb), cm Coefficient of Attenuation 0.036 0.5 0.120 10 -1 0.240 10 -2 0.358 10 -3 0.477 10 -4 Note that these estimates of attenuation do not take into consideration...

What Is Sodium Iodide I-123 Used For?

INDICATION AND USE Administration of Sodium Iodide I 123 is indicated as a diagnostic procedure to be used in evaluating thyroid function and/or morphology.

Dosage and Administration

DOSAGE AND ADMINISTRATION The recommended oral dose for the average patient (70 kg) is 3.7 to 14.8 MBq (100-400 µCi). The lower part of the dosage range 3.7 MBq (100 µCi) is recommended for uptake studies alone, and the higher part 14.8 MBq (400 µCi) for thyroid imaging. The determination of I 123 concentration in the thyroid gland may be initiated at six hours after administering the dose and should be measured in accordance with standardized procedures. The patient dose should be measured by a suitable radioactive calibration system immediately prior to administration. The capsules can be utilized up to thirty (30) hours after calibration time and date. Thereafter, discard the capsules in accordance with standard safety procedures. The user should wear waterproof gloves at all times when handling the capsules or container. Radiation Dosimetry The estimated absorbed radiation doses to several organs of an average patient (70 kg) from oral administration of the maximum dose of 14.8 MBq (400 µCi) of I 123 are shown in Table 4 for thyroid uptakes of 5, 15, and 25%. For comparison at these three values of thyroid uptake, the estimated radiation doses from doses of 3.7 MBq (100 µCi) I 131, also used as thyroid imaging agent, are also included. Table 4 Radiation Dose Estimates as a Function of Maximum Thyroid Uptake for I 123* Sodium Iodide At Time of Calibration and Expiry Compared to I 131 *Concentration at Time of Calibration: 97% I 123, 2.9% I 125, 0.1% Te 121 Concentration at Time of Expiry: 87.2% I 123, 12.4% I 125, 0.4% Te 121 All Iodine Kinetics treated as in MIRD Dose Estimate Report 5. Bladder voiding interval, 4.8 hours. Tellurium 121 dosimetry taken from ICRP 30. Target Organ Maximum Thyroid Uptake (%) Estimated Radiation Absorbed Doses I 123 mGy/14.8 MBq (rads/400 µCi) I 131 mGy/3.7 MBq (rads/100 µCi) TOC TOE Thyroid 5 25 (2.5) 75 (7.5) 260 (26) 15 77 (7.7) 230 (23) 780 (78) 25 130 (13) 410 (41) 1300 (130) Liver 5 0.089 (0.0089) 0.13 (0.013) 0.16 (0.016) 15 0.10 (0.010) 0.18 (0.018) 0.28 (0.028) 25 0.11 (0.011) 0.24 (0.024) 0.41 (0.041) Ovaries 5 0.18 (0.018) 0.19 (0.019) 0.18 (0.018) 15 0.17 (0.017) 0.18 (0.018) 0.18 (0.018) 25 0.16 (0.016) 0.18 (0.018) 0.17 (0.017) Red Marrow 5 0.12 (0.012) 0.16 (0.016) 0.15 (0.015) 15 0.12 (0.012) 0.18 (0.018) 0.21 (0.021) 25 0.13 (0.013) 0.19 (0.019) 0.27 (0.027) Stomach Wall 5 0.96 (0.096) 0.98 (0.098) 1.7 (0.17) 15 0.89 (0.089) 0.91 (0.091) 1.5 (0.15) 25 0.82 (0.082) 0.85 (0.085) 1.4 (0.14) Small Intestine 5 0.70 (0.070) 0.71 (0.071) 1.2 (0.12) 15 0.65 (0.065) 0.67 (0.067) 1.1 (0.11) 25 0.60 (0.060) 0.62 (0.062) 0.99 (0.099) Testes 5 0.076 (0.0076) 0.089 (0.0089) 0.12 (0.012) 15 0.072 (0.0072) 0.087 (0.0087) 0.12 (0.012) 25 0.068 (0.0068) 0.085 (0.0085) 0.12 (0.012) Bladder 5 1.7 (0.17) 1.7 (0.17) 2.9 (0.29) 15 1.6 (0.16) 1.6 (0.16) 2.7 (0.27) 25 1.4 (0.14) 1.5 (0.15) 2.4 (0.24) Skeleton 5 0.11 (0.011) 0.16 (0.016) 0.12 (0.012) 15 0.12 (0.012) 0.18 (0.018) 0.18 (0.018) 25 0.14 (0.014) 0.21 (0.021)...

Side Effects (Adverse Reactions)

ADVERSE REACTIONS Although rare, reactions associated with the administration of Sodium Iodide isotopes for diagnostic use include, in decreasing order of frequency, nausea, vomiting, chest pain, tachycardia, itching skin, rash and hives.

Warnings and Precautions

WARNINGS Females of childbearing age and children under 18 should not be studied unless the benefits anticipated from the performance of the test outweigh the possible risk of exposure to the amount of ionizing radiation associated with the test.

Contraindications

CONTRAINDICATIONS To date there are no known contraindications to the use of Sodium Iodide I 123 capsules.

How Supplied

HOW SUPPLIED Sodium Iodide I 123 is supplied as capsules for oral administration in strengths of 3.7 MBq (100 µCi) and 7.4 MBq (200 µCi) at time of calibration. Each gelatin capsule contains 0.45 - 0.65 g of sucrose. The capsules are packaged in plastic vials containing either one or five capsules of a single strength per vial. The plastic vial is packaged in a lead shield with a label identical to that affixed to the plastic vial. A package insert is supplied with each lead shield. The -I (Iodine) content for a 100 µCi capsule is 5.2 ng and the -I content for a 200 µCi capsule is 10.4 ng at TOC. Dispense and preserve capsules in well-closed containers that are adequately shielded. Store at room temperature, below 86°F. The contents of the capsules are radioactive. Adequate shielding and handling precautions must be maintained. THIS PACKAGE INSERT ISSUED APRIL 2018 Cardinal Health Denver, CO 80011 (303) 343-6800 Sodium Iodide I 123 1-020-16

About This Information

This drug information is sourced from FDA-approved labeling via the openFDA database. It is intended for educational and reference purposes only. This is not medical advice. Always consult your healthcare provider before making decisions about medication. Drug information may be updated by the FDA; check with your pharmacist for the most current information.

What are side effects?

Side effects are unwanted reactions that can occur when taking a medication. They range from mild (headache, nausea) to severe (allergic reactions, organ damage). Not everyone experiences side effects, and severity varies. Report any concerning side effects to your doctor.

What are drug interactions?

Drug interactions occur when a medication is affected by another drug, food, or supplement. Interactions can make medications less effective or cause dangerous side effects. Always tell your doctor about all medications and supplements you take.