Iodide I-123: uses, dosing, side effects & brands
Iodide I-123 is a medicine sold in the U.S. under one brand. Below: what the FDA label says, every product that contains it, what the pills look like, and its recall record.
Key facts
- Available as
- Capsule
- Sold as
- Sodium Iodide I 123
- Prescription?
- Prescription only
- Generic available?
- Not in our catalog
How iodide i-123 is dosed
From the FDA label for Sodium Iodide I 123 (application NDA017630). Other iodide i-123 products — different forms, different strengths — are dosed differently. Follow the label for the one you were prescribed.
The recommended oral dose for the average patient (70 kg) is 3.7 to 14.8 MBq (100 to 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 radioactivity calibration system immediately prior to administration. The capsules can be utilized up to 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. Absorbed Radiation Dose Estimates as a Function of Maximum Thyroid Uptake for Sodium Iodide I-123 * at Time of Calibration and Expiry Compared to Sodium Iodide…
Iodide I-123 side effects
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.
Who shouldn’t take iodide i-123
To date there are no known contraindications to the use of Sodium Iodide I 123 Capsules.
Every iodide i-123 product we track (1)
Same active ingredient — different manufacturer, form, price and FDA recall record. That last one is what our independent score measures.
Only one: Sodium Iodide I 123.
Related calculators
Frequently asked questions
What is iodide i-123?
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. 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 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 Te-121. The ratio of the concentration of I-123 and I-125 changes with time. Graph 1 shows the minimum concentration of I-123 as a function of time and Graph 2 shows the maximum concentration of I-125 as a function of time. Graph 1. Radionuclidic Concentration of I-123 PERCENT OF TOTAL RADIOACTIVITY: IODINE-123 Graph 2. Radionuclidic Concentration of I-125 PERCENT OF TOTAL RADIOACTIVITY: IODINE-125 Graph 1 Graph 2 Physical Characteristics Iodine-123 decays by electron capture with a physical half-life of 13.2 hours Kocher, David C., Radioactive Decay Data Tables. DOE/TIC-11026, 122 (1981). . The photon that is useful for detection and imaging studies is listed in Table 1. Table 1. Principal Radiation Emission Data Radiation Mean % Disintegration 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…
Can you take iodide i-123 with other medicines?
It depends on the medicine. We check it against the FDA labels rather than guessing: our interaction checker searches each drug's own label for the other and quotes what it says, naming the section it came from. Run iodide i-123 against whatever else you take — and remember that a label not naming a drug is not the same as that combination being safe.
What forms does iodide i-123 come in?
Across the brands we track, iodide i-123 is currently marketed as capsule, per the FDA's National Drug Code Directory. Each form is dosed differently — follow the label for the exact product you were prescribed.
Is there a generic iodide i-123?
We do not currently list a generic-labelled iodide i-123 product. That does not always mean none exists — it means none appears under a generic name in the FDA data we track. Ask your pharmacist.
Cite this page
- APA
- pharmaranks. (2026, July 24). Iodide I-123: uses, dosing, side effects & brands. https://pharmaranks.com/drugs/iodide-i-123
- MLA
- “Iodide I-123: uses, dosing, side effects & brands.” pharmaranks, 24 July 2026, https://pharmaranks.com/drugs/iodide-i-123.
We summarise public FDA and NIH sources — for a clinical claim, cite the primary source we link to as well.
Sources: FDA openFDA drug label, National Drug Code Directory, and Enforcement (recall) database. This page reproduces public FDA data and is not medical advice. Dosing is set by your prescriber.
Read the full FDA label for iodide i-123 on DailyMed (NIH) ↗.